reactos/ntoskrnl/kdbg/kdb_cli.c

/*
 *  ReactOS kernel
 *  Copyright (C) 2005 ReactOS Team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License along
 *  with this program; if not, write to the Free Software Foundation, Inc.,
 *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */
/*
 * PROJECT:         ReactOS kernel
 * FILE:            ntoskrnl/kdbg/kdb_cli.c
 * PURPOSE:         Kernel debugger command line interface
 * PROGRAMMER:      Gregor Anich (blight@blight.eu.org)
 *                  Herv<EFBFBD> Poussineau
 * UPDATE HISTORY:
 *                  Created 16/01/2005
 */

/* INCLUDES ******************************************************************/

#include <ntoskrnl.h>

#define NDEBUG
#include <debug.h>

/* DEFINES *******************************************************************/

#define KEY_BS          8
#define KEY_ESC         27
#define KEY_DEL         127

#define KEY_SCAN_UP     72
#define KEY_SCAN_DOWN   80

/* Scan codes of keyboard keys: */
#define KEYSC_END       0x004f
#define KEYSC_PAGEUP    0x0049
#define KEYSC_PAGEDOWN  0x0051
#define KEYSC_HOME      0x0047
#define KEYSC_ARROWUP   0x0048

#define KDB_ENTER_CONDITION_TO_STRING(cond)                               \
                   ((cond) == KdbDoNotEnter ? "never" :                   \
                   ((cond) == KdbEnterAlways ? "always" :                 \
                   ((cond) == KdbEnterFromKmode ? "kmode" : "umode")))

#define KDB_ACCESS_TYPE_TO_STRING(type)                                   \
                   ((type) == KdbAccessRead ? "read" :                    \
                   ((type) == KdbAccessWrite ? "write" :                  \
                   ((type) == KdbAccessReadWrite ? "rdwr" : "exec")))

#define NPX_STATE_TO_STRING(state)                                        \
                   ((state) == NPX_STATE_LOADED ? "Loaded" :              \
                   ((state) == NPX_STATE_NOT_LOADED ? "Not loaded" : "Unknown"))

/* PROTOTYPES ****************************************************************/

static BOOLEAN KdbpCmdEvalExpression(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdDisassembleX(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdRegs(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdBackTrace(ULONG Argc, PCHAR Argv[]);

static BOOLEAN KdbpCmdContinue(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdStep(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdBreakPointList(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdEnableDisableClearBreakPoint(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdBreakPoint(ULONG Argc, PCHAR Argv[]);

static BOOLEAN KdbpCmdThread(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdProc(ULONG Argc, PCHAR Argv[]);

static BOOLEAN KdbpCmdMod(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdGdtLdtIdt(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdPcr(ULONG Argc, PCHAR Argv[]);
#ifdef _M_IX86
static BOOLEAN KdbpCmdTss(ULONG Argc, PCHAR Argv[]);
#endif

static BOOLEAN KdbpCmdBugCheck(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdReboot(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdFilter(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdSet(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdHelp(ULONG Argc, PCHAR Argv[]);
static BOOLEAN KdbpCmdDmesg(ULONG Argc, PCHAR Argv[]);

BOOLEAN ExpKdbgExtPool(ULONG Argc, PCHAR Argv[]);
BOOLEAN ExpKdbgExtPoolUsed(ULONG Argc, PCHAR Argv[]);
BOOLEAN ExpKdbgExtPoolFind(ULONG Argc, PCHAR Argv[]);
BOOLEAN ExpKdbgExtFileCache(ULONG Argc, PCHAR Argv[]);
BOOLEAN ExpKdbgExtDefWrites(ULONG Argc, PCHAR Argv[]);
BOOLEAN ExpKdbgExtIrpFind(ULONG Argc, PCHAR Argv[]);
BOOLEAN ExpKdbgExtHandle(ULONG Argc, PCHAR Argv[]);

#ifdef __ROS_DWARF__
static BOOLEAN KdbpCmdPrintStruct(ULONG Argc, PCHAR Argv[]);
#endif

/* Be more descriptive than intrinsics */
#ifndef Ke386GetGlobalDescriptorTable
# define Ke386GetGlobalDescriptorTable __sgdt
#endif
#ifndef Ke386GetLocalDescriptorTable
# define Ke386GetLocalDescriptorTable __sldt
#endif

/* Portability */
FORCEINLINE
ULONG_PTR
strtoulptr(const char* nptr, char** endptr, int base)
{
#ifdef _M_IX86
    return strtoul(nptr, endptr, base);
#else
    return strtoull(nptr, endptr, base);
#endif
}

/* GLOBALS *******************************************************************/

typedef
BOOLEAN
(NTAPI *PKDBG_CLI_ROUTINE)(
    IN PCHAR Command,
    IN ULONG Argc,
    IN PCH Argv[]);

static PKDBG_CLI_ROUTINE KdbCliCallbacks[10];
static BOOLEAN KdbUseIntelSyntax = FALSE; /* Set to TRUE for intel syntax */
static BOOLEAN KdbBreakOnModuleLoad = FALSE; /* Set to TRUE to break into KDB when a module is loaded */

static CHAR KdbCommandHistoryBuffer[2048]; /* Command history string ringbuffer */
static PCHAR KdbCommandHistory[sizeof(KdbCommandHistoryBuffer) / 8] = { NULL }; /* Command history ringbuffer */
static LONG KdbCommandHistoryBufferIndex = 0;
static LONG KdbCommandHistoryIndex = 0;

static ULONG KdbNumberOfRowsPrinted = 0;
static ULONG KdbNumberOfColsPrinted = 0;
static BOOLEAN KdbOutputAborted = FALSE;
static BOOLEAN KdbRepeatLastCommand = FALSE;
static LONG KdbNumberOfRowsTerminal = -1;
static LONG KdbNumberOfColsTerminal = -1;

PCHAR KdbInitFileBuffer = NULL; /* Buffer where KDBinit file is loaded into during initialization */
BOOLEAN KdbpBugCheckRequested = FALSE;

/* Vars for dmesg */
/* defined in ../kd/kdio.c, declare here: */
extern volatile BOOLEAN KdbpIsInDmesgMode;
extern const ULONG KdpDmesgBufferSize;
extern PCHAR KdpDmesgBuffer;
extern volatile ULONG KdpDmesgCurrentPosition;
extern volatile ULONG KdpDmesgFreeBytes;
extern volatile ULONG KdbDmesgTotalWritten;

STRING KdbPromptString = RTL_CONSTANT_STRING("kdb:> ");

//
// Debug Filter Component Table
//
#define KD_DEBUG_PRINT_FILTER(Name) \
    { #Name, DPFLTR_##Name##_ID }

static struct
{
    PCSTR Name;
    ULONG Id;
}
ComponentTable[] =
{
//
// Default components
//
    { "WIN2000", MAXULONG },
    KD_DEBUG_PRINT_FILTER(DEFAULT),
//
// Standard components
//
    KD_DEBUG_PRINT_FILTER(SYSTEM),
    KD_DEBUG_PRINT_FILTER(SMSS),
    KD_DEBUG_PRINT_FILTER(SETUP),
    KD_DEBUG_PRINT_FILTER(NTFS),
    KD_DEBUG_PRINT_FILTER(FSTUB),
    KD_DEBUG_PRINT_FILTER(CRASHDUMP),
    KD_DEBUG_PRINT_FILTER(CDAUDIO),
    KD_DEBUG_PRINT_FILTER(CDROM),
    KD_DEBUG_PRINT_FILTER(CLASSPNP),
    KD_DEBUG_PRINT_FILTER(DISK),
    KD_DEBUG_PRINT_FILTER(REDBOOK),
    KD_DEBUG_PRINT_FILTER(STORPROP),
    KD_DEBUG_PRINT_FILTER(SCSIPORT),
    KD_DEBUG_PRINT_FILTER(SCSIMINIPORT),
    KD_DEBUG_PRINT_FILTER(CONFIG),
    KD_DEBUG_PRINT_FILTER(I8042PRT),
    KD_DEBUG_PRINT_FILTER(SERMOUSE),
    KD_DEBUG_PRINT_FILTER(LSERMOUS),
    KD_DEBUG_PRINT_FILTER(KBDHID),
    KD_DEBUG_PRINT_FILTER(MOUHID),
    KD_DEBUG_PRINT_FILTER(KBDCLASS),
    KD_DEBUG_PRINT_FILTER(MOUCLASS),
    KD_DEBUG_PRINT_FILTER(TWOTRACK),
    KD_DEBUG_PRINT_FILTER(WMILIB),
    KD_DEBUG_PRINT_FILTER(ACPI),
    KD_DEBUG_PRINT_FILTER(AMLI),
    KD_DEBUG_PRINT_FILTER(HALIA64),
    KD_DEBUG_PRINT_FILTER(VIDEO),
    KD_DEBUG_PRINT_FILTER(SVCHOST),
    KD_DEBUG_PRINT_FILTER(VIDEOPRT),
    KD_DEBUG_PRINT_FILTER(TCPIP),
    KD_DEBUG_PRINT_FILTER(DMSYNTH),
    KD_DEBUG_PRINT_FILTER(NTOSPNP),
    KD_DEBUG_PRINT_FILTER(FASTFAT),
    KD_DEBUG_PRINT_FILTER(SAMSS),
    KD_DEBUG_PRINT_FILTER(PNPMGR),
    KD_DEBUG_PRINT_FILTER(NETAPI),
    KD_DEBUG_PRINT_FILTER(SCSERVER),
    KD_DEBUG_PRINT_FILTER(SCCLIENT),
    KD_DEBUG_PRINT_FILTER(SERIAL),
    KD_DEBUG_PRINT_FILTER(SERENUM),
    KD_DEBUG_PRINT_FILTER(UHCD),
    KD_DEBUG_PRINT_FILTER(RPCPROXY),
    KD_DEBUG_PRINT_FILTER(AUTOCHK),
    KD_DEBUG_PRINT_FILTER(DCOMSS),
    KD_DEBUG_PRINT_FILTER(UNIMODEM),
    KD_DEBUG_PRINT_FILTER(SIS),
    KD_DEBUG_PRINT_FILTER(FLTMGR),
    KD_DEBUG_PRINT_FILTER(WMICORE),
    KD_DEBUG_PRINT_FILTER(BURNENG),
    KD_DEBUG_PRINT_FILTER(IMAPI),
    KD_DEBUG_PRINT_FILTER(SXS),
    KD_DEBUG_PRINT_FILTER(FUSION),
    KD_DEBUG_PRINT_FILTER(IDLETASK),
    KD_DEBUG_PRINT_FILTER(SOFTPCI),
    KD_DEBUG_PRINT_FILTER(TAPE),
    KD_DEBUG_PRINT_FILTER(MCHGR),
    KD_DEBUG_PRINT_FILTER(IDEP),
    KD_DEBUG_PRINT_FILTER(PCIIDE),
    KD_DEBUG_PRINT_FILTER(FLOPPY),
    KD_DEBUG_PRINT_FILTER(FDC),
    KD_DEBUG_PRINT_FILTER(TERMSRV),
    KD_DEBUG_PRINT_FILTER(W32TIME),
    KD_DEBUG_PRINT_FILTER(PREFETCHER),
    KD_DEBUG_PRINT_FILTER(RSFILTER),
    KD_DEBUG_PRINT_FILTER(FCPORT),
    KD_DEBUG_PRINT_FILTER(PCI),
    KD_DEBUG_PRINT_FILTER(DMIO),
    KD_DEBUG_PRINT_FILTER(DMCONFIG),
    KD_DEBUG_PRINT_FILTER(DMADMIN),
    KD_DEBUG_PRINT_FILTER(WSOCKTRANSPORT),
    KD_DEBUG_PRINT_FILTER(VSS),
    KD_DEBUG_PRINT_FILTER(PNPMEM),
    KD_DEBUG_PRINT_FILTER(PROCESSOR),
    KD_DEBUG_PRINT_FILTER(DMSERVER),
    KD_DEBUG_PRINT_FILTER(SR),
    KD_DEBUG_PRINT_FILTER(INFINIBAND),
    KD_DEBUG_PRINT_FILTER(IHVDRIVER),
    KD_DEBUG_PRINT_FILTER(IHVVIDEO),
    KD_DEBUG_PRINT_FILTER(IHVAUDIO),
    KD_DEBUG_PRINT_FILTER(IHVNETWORK),
    KD_DEBUG_PRINT_FILTER(IHVSTREAMING),
    KD_DEBUG_PRINT_FILTER(IHVBUS),
    KD_DEBUG_PRINT_FILTER(HPS),
    KD_DEBUG_PRINT_FILTER(RTLTHREADPOOL),
    KD_DEBUG_PRINT_FILTER(LDR),
    KD_DEBUG_PRINT_FILTER(TCPIP6),
    KD_DEBUG_PRINT_FILTER(ISAPNP),
    KD_DEBUG_PRINT_FILTER(SHPC),
    KD_DEBUG_PRINT_FILTER(STORPORT),
    KD_DEBUG_PRINT_FILTER(STORMINIPORT),
    KD_DEBUG_PRINT_FILTER(PRINTSPOOLER),
    KD_DEBUG_PRINT_FILTER(VSSDYNDISK),
    KD_DEBUG_PRINT_FILTER(VERIFIER),
    KD_DEBUG_PRINT_FILTER(VDS),
    KD_DEBUG_PRINT_FILTER(VDSBAS),
    KD_DEBUG_PRINT_FILTER(VDSDYN),  // Specified in Vista+
    KD_DEBUG_PRINT_FILTER(VDSDYNDR),
    KD_DEBUG_PRINT_FILTER(VDSLDR),  // Specified in Vista+
    KD_DEBUG_PRINT_FILTER(VDSUTIL),
    KD_DEBUG_PRINT_FILTER(DFRGIFC),
    KD_DEBUG_PRINT_FILTER(MM),
    KD_DEBUG_PRINT_FILTER(DFSC),
    KD_DEBUG_PRINT_FILTER(WOW64),
//
// Components specified in Vista+, some of which we also use in ReactOS
//
    KD_DEBUG_PRINT_FILTER(ALPC),
    KD_DEBUG_PRINT_FILTER(WDI),
    KD_DEBUG_PRINT_FILTER(PERFLIB),
    KD_DEBUG_PRINT_FILTER(KTM),
    KD_DEBUG_PRINT_FILTER(IOSTRESS),
    KD_DEBUG_PRINT_FILTER(HEAP),
    KD_DEBUG_PRINT_FILTER(WHEA),
    KD_DEBUG_PRINT_FILTER(USERGDI),
    KD_DEBUG_PRINT_FILTER(MMCSS),
    KD_DEBUG_PRINT_FILTER(TPM),
    KD_DEBUG_PRINT_FILTER(THREADORDER),
    KD_DEBUG_PRINT_FILTER(ENVIRON),
    KD_DEBUG_PRINT_FILTER(EMS),
    KD_DEBUG_PRINT_FILTER(WDT),
    KD_DEBUG_PRINT_FILTER(FVEVOL),
    KD_DEBUG_PRINT_FILTER(NDIS),
    KD_DEBUG_PRINT_FILTER(NVCTRACE),
    KD_DEBUG_PRINT_FILTER(LUAFV),
    KD_DEBUG_PRINT_FILTER(APPCOMPAT),
    KD_DEBUG_PRINT_FILTER(USBSTOR),
    KD_DEBUG_PRINT_FILTER(SBP2PORT),
    KD_DEBUG_PRINT_FILTER(COVERAGE),
    KD_DEBUG_PRINT_FILTER(CACHEMGR),
    KD_DEBUG_PRINT_FILTER(MOUNTMGR),
    KD_DEBUG_PRINT_FILTER(CFR),
    KD_DEBUG_PRINT_FILTER(TXF),
    KD_DEBUG_PRINT_FILTER(KSECDD),
    KD_DEBUG_PRINT_FILTER(FLTREGRESS),
    KD_DEBUG_PRINT_FILTER(MPIO),
    KD_DEBUG_PRINT_FILTER(MSDSM),
    KD_DEBUG_PRINT_FILTER(UDFS),
    KD_DEBUG_PRINT_FILTER(PSHED),
    KD_DEBUG_PRINT_FILTER(STORVSP),
    KD_DEBUG_PRINT_FILTER(LSASS),
    KD_DEBUG_PRINT_FILTER(SSPICLI),
    KD_DEBUG_PRINT_FILTER(CNG),
    KD_DEBUG_PRINT_FILTER(EXFAT),
    KD_DEBUG_PRINT_FILTER(FILETRACE),
    KD_DEBUG_PRINT_FILTER(XSAVE),
    KD_DEBUG_PRINT_FILTER(SE),
    KD_DEBUG_PRINT_FILTER(DRIVEEXTENDER),
//
// Components specified in Windows 8
//
    KD_DEBUG_PRINT_FILTER(POWER),
    KD_DEBUG_PRINT_FILTER(CRASHDUMPXHCI),
    KD_DEBUG_PRINT_FILTER(GPIO),
    KD_DEBUG_PRINT_FILTER(REFS),
    KD_DEBUG_PRINT_FILTER(WER),
//
// Components specified in Windows 10
//
    KD_DEBUG_PRINT_FILTER(CAPIMG),
    KD_DEBUG_PRINT_FILTER(VPCI),
    KD_DEBUG_PRINT_FILTER(STORAGECLASSMEMORY),
    KD_DEBUG_PRINT_FILTER(FSLIB),
};
#undef KD_DEBUG_PRINT_FILTER

//
// Command Table
//
static const struct
{
    PCHAR Name;
    PCHAR Syntax;
    PCHAR Help;
    BOOLEAN (*Fn)(ULONG Argc, PCHAR Argv[]);
} KdbDebuggerCommands[] = {
    /* Data */
    { NULL, NULL, "Data", NULL },
    { "?", "? expression", "Evaluate expression.", KdbpCmdEvalExpression },
    { "disasm", "disasm [address] [L count]", "Disassemble count instructions at address.", KdbpCmdDisassembleX },
    { "x", "x [address] [L count]", "Display count dwords, starting at address.", KdbpCmdDisassembleX },
    { "regs", "regs", "Display general purpose registers.", KdbpCmdRegs },
    { "sregs", "sregs", "Display status registers.", KdbpCmdRegs },
    { "dregs", "dregs", "Display debug registers.", KdbpCmdRegs },
    { "bt", "bt [*frameaddr|thread id]", "Prints current backtrace or from given frame address.", KdbpCmdBackTrace },
#ifdef __ROS_DWARF__
    { "dt", "dt [mod] [type] [addr]", "Print a struct. The address is optional.", KdbpCmdPrintStruct },
#endif

    /* Flow control */
    { NULL, NULL, "Flow control", NULL },
    { "cont", "cont", "Continue execution (leave debugger).", KdbpCmdContinue },
    { "step", "step [count]", "Execute single instructions, stepping into interrupts.", KdbpCmdStep },
    { "next", "next [count]", "Execute single instructions, skipping calls and reps.", KdbpCmdStep },
    { "bl", "bl", "List breakpoints.", KdbpCmdBreakPointList },
    { "be", "be [breakpoint]", "Enable breakpoint.", KdbpCmdEnableDisableClearBreakPoint },
    { "bd", "bd [breakpoint]", "Disable breakpoint.", KdbpCmdEnableDisableClearBreakPoint },
    { "bc", "bc [breakpoint]", "Clear breakpoint.", KdbpCmdEnableDisableClearBreakPoint },
    { "bpx", "bpx [address] [IF condition]", "Set software execution breakpoint at address.", KdbpCmdBreakPoint },
    { "bpm", "bpm [r|w|rw|x] [byte|word|dword] [address] [IF condition]", "Set memory breakpoint at address.", KdbpCmdBreakPoint },

    /* Process/Thread */
    { NULL, NULL, "Process/Thread", NULL },
    { "thread", "thread [list[ pid]|[attach ]tid]", "List threads in current or specified process, display thread with given id or attach to thread.", KdbpCmdThread },
    { "proc", "proc [list|[attach ]pid]", "List processes, display process with given id or attach to process.", KdbpCmdProc },

    /* System information */
    { NULL, NULL, "System info", NULL },
    { "mod", "mod [address]", "List all modules or the one containing address.", KdbpCmdMod },
    { "gdt", "gdt", "Display the global descriptor table.", KdbpCmdGdtLdtIdt },
    { "ldt", "ldt", "Display the local descriptor table.", KdbpCmdGdtLdtIdt },
    { "idt", "idt", "Display the interrupt descriptor table.", KdbpCmdGdtLdtIdt },
    { "pcr", "pcr", "Display the processor control region.", KdbpCmdPcr },
#ifdef _M_IX86
    { "tss", "tss [selector|*descaddr]", "Display the current task state segment, or the one specified by its selector number or descriptor address.", KdbpCmdTss },
#endif

    /* Others */
    { NULL, NULL, "Others", NULL },
    { "bugcheck", "bugcheck", "Bugchecks the system.", KdbpCmdBugCheck },
    { "reboot", "reboot", "Reboots the system.", KdbpCmdReboot},
    { "filter", "filter [error|warning|trace|info|level]+|-[componentname|default]", "Enable/disable debug channels.", KdbpCmdFilter },
    { "set", "set [var] [value]", "Sets var to value or displays value of var.", KdbpCmdSet },
    { "dmesg", "dmesg", "Display debug messages on screen, with navigation on pages.", KdbpCmdDmesg },
    { "kmsg", "kmsg", "Kernel dmesg. Alias for dmesg.", KdbpCmdDmesg },
    { "help", "help", "Display help screen.", KdbpCmdHelp },
    { "!pool", "!pool [Address [Flags]]", "Display information about pool allocations.", ExpKdbgExtPool },
    { "!poolused", "!poolused [Flags [Tag]]", "Display pool usage.", ExpKdbgExtPoolUsed },
    { "!poolfind", "!poolfind Tag [Pool]", "Search for pool tag allocations.", ExpKdbgExtPoolFind },
    { "!filecache", "!filecache", "Display cache usage.", ExpKdbgExtFileCache },
    { "!defwrites", "!defwrites", "Display cache write values.", ExpKdbgExtDefWrites },
    { "!irpfind", "!irpfind [Pool [startaddress [criteria data]]]", "Lists IRPs potentially matching criteria.", ExpKdbgExtIrpFind },
    { "!handle", "!handle [Handle]", "Displays info about handles.", ExpKdbgExtHandle },
};

/* FUNCTIONS *****************************************************************/

/*!\brief Evaluates an expression...
 *
 * Much like KdbpRpnEvaluateExpression, but prints the error message (if any)
 * at the given offset.
 *
 * \param Expression  Expression to evaluate.
 * \param ErrOffset   Offset (in characters) to print the error message at.
 * \param Result      Receives the result on success.
 *
 * \retval TRUE   Success.
 * \retval FALSE  Failure.
 */
static BOOLEAN
KdbpEvaluateExpression(
    IN  PCHAR Expression,
    IN  LONG ErrOffset,
    OUT PULONGLONG Result)
{
    static CHAR ErrMsgBuffer[130] = "^ ";
    LONG ExpressionErrOffset = -1;
    PCHAR ErrMsg = ErrMsgBuffer;
    BOOLEAN Ok;

    Ok = KdbpRpnEvaluateExpression(Expression, KdbCurrentTrapFrame, Result,
                                   &ExpressionErrOffset, ErrMsgBuffer + 2);
    if (!Ok)
    {
        if (ExpressionErrOffset >= 0)
            ExpressionErrOffset += ErrOffset;
        else
            ErrMsg += 2;

        KdbpPrint("%*s%s\n", ExpressionErrOffset, "", ErrMsg);
    }

    return Ok;
}

BOOLEAN
NTAPI
KdbpGetHexNumber(
    IN PCHAR pszNum,
    OUT ULONG_PTR *pulValue)
{
    char *endptr;

    /* Skip optional '0x' prefix */
    if ((pszNum[0] == '0') && ((pszNum[1] == 'x') || (pszNum[1] == 'X')))
        pszNum += 2;

    /* Make a number from the string (hex) */
    *pulValue = strtoul(pszNum, &endptr, 16);

    return (*endptr == '\0');
}

/*!\brief Evaluates an expression and displays the result.
 */
static BOOLEAN
KdbpCmdEvalExpression(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG i, len;
    ULONGLONG Result = 0;
    ULONG ul;
    LONG l = 0;
    BOOLEAN Ok;

    if (Argc < 2)
    {
        KdbpPrint("?: Argument required\n");
        return TRUE;
    }

    /* Put the arguments back together */
    Argc--;
    for (i = 1; i < Argc; i++)
    {
        len = strlen(Argv[i]);
        Argv[i][len] = ' ';
    }

    /* Evaluate the expression */
    Ok = KdbpEvaluateExpression(Argv[1], KdbPromptString.Length + (Argv[1]-Argv[0]), &Result);
    if (Ok)
    {
        if (Result > 0x00000000ffffffffLL)
        {
            if (Result & 0x8000000000000000LL)
                KdbpPrint("0x%016I64x  %20I64u  %20I64d\n", Result, Result, Result);
            else
                KdbpPrint("0x%016I64x  %20I64u\n", Result, Result);
        }
        else
        {
            ul = (ULONG)Result;

            if (ul <= 0xff && ul >= 0x80)
                l = (LONG)((CHAR)ul);
            else if (ul <= 0xffff && ul >= 0x8000)
                l = (LONG)((SHORT)ul);
            else
                l = (LONG)ul;

            if (l < 0)
                KdbpPrint("0x%08lx  %10lu  %10ld\n", ul, ul, l);
            else
                KdbpPrint("0x%08lx  %10lu\n", ul, ul);
        }
    }

    return TRUE;
}

#ifdef __ROS_DWARF__

/*!\brief Print a struct
 */
static VOID
KdbpPrintStructInternal
(PROSSYM_INFO Info,
 PCHAR Indent,
 BOOLEAN DoRead,
 PVOID BaseAddress,
 PROSSYM_AGGREGATE Aggregate)
{
    ULONG i;
    ULONGLONG Result;
    PROSSYM_AGGREGATE_MEMBER Member;
    ULONG IndentLen = strlen(Indent);
    ROSSYM_AGGREGATE MemberAggregate = {0 };

    for (i = 0; i < Aggregate->NumElements; i++) {
        Member = &Aggregate->Elements[i];
        KdbpPrint("%s%p+%x: %s", Indent, ((PCHAR)BaseAddress) + Member->BaseOffset, Member->Size, Member->Name ? Member->Name : "<anoymous>");
        if (DoRead) {
            if (!strcmp(Member->Type, "_UNICODE_STRING")) {
                KdbpPrint("\"%wZ\"\n", ((PCHAR)BaseAddress) + Member->BaseOffset);
                continue;
            } else if (!strcmp(Member->Type, "PUNICODE_STRING")) {
                KdbpPrint("\"%wZ\"\n", *(((PUNICODE_STRING*)((PCHAR)BaseAddress) + Member->BaseOffset)));
                continue;
            }
            switch (Member->Size) {
            case 1:
            case 2:
            case 4:
            case 8: {
                Result = 0;
                if (NT_SUCCESS(KdbpSafeReadMemory(&Result, ((PCHAR)BaseAddress) + Member->BaseOffset, Member->Size))) {
                    if (Member->Bits) {
                        Result >>= Member->FirstBit;
                        Result &= ((1 << Member->Bits) - 1);
                    }
                    KdbpPrint(" %lx\n", Result);
                }
                else goto readfail;
                break;
            }
            default: {
                if (Member->Size < 8) {
                    if (NT_SUCCESS(KdbpSafeReadMemory(&Result, ((PCHAR)BaseAddress) + Member->BaseOffset, Member->Size))) {
                        ULONG j;
                        for (j = 0; j < Member->Size; j++) {
                            KdbpPrint(" %02x", (int)(Result & 0xff));
                            Result >>= 8;
                        }
                    } else goto readfail;
                } else {
                    KdbpPrint(" %s @ %p {\n", Member->Type, ((PCHAR)BaseAddress) + Member->BaseOffset);
                    Indent[IndentLen] = ' ';
                    if (RosSymAggregate(Info, Member->Type, &MemberAggregate)) {
                        KdbpPrintStructInternal(Info, Indent, DoRead, ((PCHAR)BaseAddress) + Member->BaseOffset, &MemberAggregate);
                        RosSymFreeAggregate(&MemberAggregate);
                    }
                    Indent[IndentLen] = 0;
                    KdbpPrint("%s}\n", Indent);
                } break;
            }
            }
        } else {
        readfail:
            if (Member->Size <= 8) {
                KdbpPrint(" ??\n");
            } else {
                KdbpPrint(" %s @ %x {\n", Member->Type, Member->BaseOffset);
                Indent[IndentLen] = ' ';
                if (RosSymAggregate(Info, Member->Type, &MemberAggregate)) {
                    KdbpPrintStructInternal(Info, Indent, DoRead, BaseAddress, &MemberAggregate);
                    RosSymFreeAggregate(&MemberAggregate);
                }
                Indent[IndentLen] = 0;
                KdbpPrint("%s}\n", Indent);
            }
        }
    }
}

PROSSYM_INFO KdbpSymFindCachedFile(PUNICODE_STRING ModName);

static BOOLEAN
KdbpCmdPrintStruct(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG i;
    ULONGLONG Result = 0;
    PVOID BaseAddress = 0;
    ROSSYM_AGGREGATE Aggregate = {0};
    UNICODE_STRING ModName = {0};
    ANSI_STRING AnsiName = {0};
    CHAR Indent[100] = {0};
    PROSSYM_INFO Info;

    if (Argc < 3) goto end;
    AnsiName.Length = AnsiName.MaximumLength = strlen(Argv[1]);
    AnsiName.Buffer = Argv[1];
    RtlAnsiStringToUnicodeString(&ModName, &AnsiName, TRUE);
    Info = KdbpSymFindCachedFile(&ModName);

    if (!Info || !RosSymAggregate(Info, Argv[2], &Aggregate)) {
        DPRINT1("Could not get aggregate\n");
        goto end;
    }

    // Get an argument for location if it was given
    if (Argc > 3) {
        ULONG len;
        PCHAR ArgStart = Argv[3];
        DPRINT1("Trying to get expression\n");
        for (i = 3; i < Argc - 1; i++)
        {
            len = strlen(Argv[i]);
            Argv[i][len] = ' ';
        }

        /* Evaluate the expression */
        DPRINT1("Arg: %s\n", ArgStart);
        if (KdbpEvaluateExpression(ArgStart, strlen(ArgStart), &Result)) {
            BaseAddress = (PVOID)(ULONG_PTR)Result;
            DPRINT1("BaseAddress: %p\n", BaseAddress);
        }
    }
    DPRINT1("BaseAddress %p\n", BaseAddress);
    KdbpPrintStructInternal(Info, Indent, !!BaseAddress, BaseAddress, &Aggregate);
end:
    RosSymFreeAggregate(&Aggregate);
    RtlFreeUnicodeString(&ModName);
    return TRUE;
}
#endif

/*!\brief Retrieves the component ID corresponding to a given component name.
 *
 * \param ComponentName  The name of the component.
 * \param ComponentId    Receives the component id on success.
 *
 * \retval TRUE   Success.
 * \retval FALSE  Failure.
 */
static BOOLEAN
KdbpGetComponentId(
    IN  PCSTR ComponentName,
    OUT PULONG ComponentId)
{
    ULONG i;

    for (i = 0; i < RTL_NUMBER_OF(ComponentTable); i++)
    {
        if (_stricmp(ComponentName, ComponentTable[i].Name) == 0)
        {
            *ComponentId = ComponentTable[i].Id;
            return TRUE;
        }
    }

    return FALSE;
}

/*!\brief Displays the list of active debug channels, or enable/disable debug channels.
 */
static BOOLEAN
KdbpCmdFilter(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG i, j, ComponentId, Level;
    ULONG set = DPFLTR_MASK, clear = DPFLTR_MASK;
    PCHAR pend;
    PCSTR opt, p;

    static struct
    {
        PCSTR Name;
        ULONG Level;
    }
    debug_classes[] =
    {
        { "error",   1 << DPFLTR_ERROR_LEVEL   },
        { "warning", 1 << DPFLTR_WARNING_LEVEL },
        { "trace",   1 << DPFLTR_TRACE_LEVEL   },
        { "info",    1 << DPFLTR_INFO_LEVEL    },
    };

    if (Argc <= 1)
    {
        /* Display the list of available debug filter components */
        KdbpPrint("REMARKS:\n"
                  "- The 'WIN2000' system-wide debug filter component is used for DbgPrint()\n"
                  "  messages without Component ID and Level.\n"
                  "- The 'DEFAULT' debug filter component is used for DbgPrint() messages with\n"
                  "  an unknown Component ID.\n\n");
        KdbpPrint("The list of debug filter components currently available on your system is:\n\n");
        KdbpPrint("    Component Name         Component ID\n"
                  "  ==================     ================\n");
        for (i = 0; i < RTL_NUMBER_OF(ComponentTable); i++)
        {
            KdbpPrint("%20s        0x%08lx\n", ComponentTable[i].Name, ComponentTable[i].Id);
        }
        return TRUE;
    }

    for (i = 1; i < Argc; i++)
    {
        opt = Argv[i];
        p = opt + strcspn(opt, "+-");
        if (!p[0]) p = opt; /* Assume it's a debug channel name */

        if (p > opt)
        {
            for (j = 0; j < RTL_NUMBER_OF(debug_classes); j++)
            {
                SIZE_T len = strlen(debug_classes[j].Name);
                if (len != (p - opt))
                    continue;
                if (_strnicmp(opt, debug_classes[j].Name, len) == 0) /* Found it */
                {
                    if (*p == '+')
                        set |= debug_classes[j].Level;
                    else
                        clear |= debug_classes[j].Level;
                    break;
                }
            }
            if (j == RTL_NUMBER_OF(debug_classes))
            {
                Level = strtoul(opt, &pend, 0);
                if (pend != p)
                {
                    KdbpPrint("filter: bad class name '%.*s'\n", p - opt, opt);
                    continue;
                }
                if (*p == '+')
                    set |= Level;
                else
                    clear |= Level;
            }
        }
        else
        {
            if (*p == '-')
                clear = MAXULONG;
            else
                set = MAXULONG;
        }
        if (*p == '+' || *p == '-')
            p++;

        if (!KdbpGetComponentId(p, &ComponentId))
        {
            KdbpPrint("filter: '%s' is not a valid component name!\n", p);
            return TRUE;
        }

        /* Get current mask value */
        NtSetDebugFilterState(ComponentId, set, TRUE);
        NtSetDebugFilterState(ComponentId, clear, FALSE);
    }

    return TRUE;
}

/*!\brief Disassembles 10 instructions at eip or given address or
 *        displays 16 dwords from memory at given address.
 */
static BOOLEAN
KdbpCmdDisassembleX(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG Count;
    ULONG ul;
    INT i;
    ULONGLONG Result = 0;
    ULONG_PTR Address = KeGetContextPc(KdbCurrentTrapFrame);
    LONG InstLen;

    if (Argv[0][0] == 'x') /* display memory */
        Count = 16;
    else /* disassemble */
        Count = 10;

    if (Argc >= 2)
    {
        /* Check for [L count] part */
        ul = 0;
        if (strcmp(Argv[Argc-2], "L") == 0)
        {
            ul = strtoul(Argv[Argc-1], NULL, 0);
            if (ul > 0)
            {
                Count = ul;
                Argc -= 2;
            }
        }
        else if (Argv[Argc-1][0] == 'L')
        {
            ul = strtoul(Argv[Argc-1] + 1, NULL, 0);
            if (ul > 0)
            {
                Count = ul;
                Argc--;
            }
        }

        /* Put the remaining arguments back together */
        Argc--;
        for (ul = 1; ul < Argc; ul++)
        {
            Argv[ul][strlen(Argv[ul])] = ' ';
        }
        Argc++;
    }

    /* Evaluate the expression */
    if (Argc > 1)
    {
        if (!KdbpEvaluateExpression(Argv[1], KdbPromptString.Length + (Argv[1]-Argv[0]), &Result))
            return TRUE;

        if (Result > (ULONGLONG)(~((ULONG_PTR)0)))
            KdbpPrint("Warning: Address %I64x is beeing truncated\n",Result);

        Address = (ULONG_PTR)Result;
    }
    else if (Argv[0][0] == 'x')
    {
        KdbpPrint("x: Address argument required.\n");
        return TRUE;
    }

    if (Argv[0][0] == 'x')
    {
        /* Display dwords */
        ul = 0;

        while (Count > 0)
        {
            if (!KdbSymPrintAddress((PVOID)Address, NULL))
                KdbpPrint("<%08x>:", Address);
            else
                KdbpPrint(":");

            i = min(4, Count);
            Count -= i;

            while (--i >= 0)
            {
                if (!NT_SUCCESS(KdbpSafeReadMemory(&ul, (PVOID)Address, sizeof(ul))))
                    KdbpPrint(" ????????");
                else
                    KdbpPrint(" %08x", ul);

                Address += sizeof(ul);
            }

            KdbpPrint("\n");
        }
    }
    else
    {
        /* Disassemble */
        while (Count-- > 0)
        {
            if (!KdbSymPrintAddress((PVOID)Address, NULL))
                KdbpPrint("<%08x>: ", Address);
            else
                KdbpPrint(": ");

            InstLen = KdbpDisassemble(Address, KdbUseIntelSyntax);
            if (InstLen < 0)
            {
                KdbpPrint("<INVALID>\n");
                return TRUE;
            }

            KdbpPrint("\n");
            Address += InstLen;
        }
    }

    return TRUE;
}

/*!\brief Displays CPU registers.
 */
static BOOLEAN
KdbpCmdRegs(
    ULONG Argc,
    PCHAR Argv[])
{
    PCONTEXT Context = KdbCurrentTrapFrame;
    INT i;
    static const PCHAR EflagsBits[32] = { " CF", NULL, " PF", " BIT3", " AF", " BIT5",
                                          " ZF", " SF", " TF", " IF", " DF", " OF",
                                          NULL, NULL, " NT", " BIT15", " RF", " VF",
                                          " AC", " VIF", " VIP", " ID", " BIT22",
                                          " BIT23", " BIT24", " BIT25", " BIT26",
                                          " BIT27", " BIT28", " BIT29", " BIT30",
                                          " BIT31" };

    if (Argv[0][0] == 'r') /* regs */
    {
#ifdef _M_IX86
        KdbpPrint("CS:EIP  0x%04x:0x%08x\n"
                  "SS:ESP  0x%04x:0x%08x\n"
                  "   EAX  0x%08x   EBX  0x%08x\n"
                  "   ECX  0x%08x   EDX  0x%08x\n"
                  "   ESI  0x%08x   EDI  0x%08x\n"
                  "   EBP  0x%08x\n",
                  Context->SegCs & 0xFFFF, Context->Eip,
                  Context->SegSs, Context->Esp,
                  Context->Eax, Context->Ebx,
                  Context->Ecx, Context->Edx,
                  Context->Esi, Context->Edi,
                  Context->Ebp);
#else
        KdbpPrint("CS:RIP  0x%04x:0x%p\n"
                  "SS:RSP  0x%04x:0x%p\n"
                  "   RAX  0x%p     RBX  0x%p\n"
                  "   RCX  0x%p     RDX  0x%p\n"
                  "   RSI  0x%p     RDI  0x%p\n"
                  "   RBP  0x%p\n",
                  Context->SegCs & 0xFFFF, Context->Rip,
                  Context->SegSs, Context->Rsp,
                  Context->Rax, Context->Rbx,
                  Context->Rcx, Context->Rdx,
                  Context->Rsi, Context->Rdi,
                  Context->Rbp);
#endif
        /* Display the EFlags */
        KdbpPrint("EFLAGS  0x%08x ", Context->EFlags);
        for (i = 0; i < 32; i++)
        {
            if (i == 1)
            {
                if ((Context->EFlags & (1 << 1)) == 0)
                    KdbpPrint(" !BIT1");
            }
            else if (i == 12)
            {
                KdbpPrint(" IOPL%d", (Context->EFlags >> 12) & 3);
            }
            else if (i == 13)
            {
            }
            else if ((Context->EFlags & (1 << i)) != 0)
            {
                KdbpPrint(EflagsBits[i]);
            }
        }
        KdbpPrint("\n");
    }
    else if (Argv[0][0] == 's') /* sregs */
    {
        KdbpPrint("CS  0x%04x  Index 0x%04x  %cDT RPL%d\n",
                  Context->SegCs & 0xffff, (Context->SegCs & 0xffff) >> 3,
                  (Context->SegCs & (1 << 2)) ? 'L' : 'G', Context->SegCs & 3);
        KdbpPrint("DS  0x%04x  Index 0x%04x  %cDT RPL%d\n",
                  Context->SegDs, Context->SegDs >> 3, (Context->SegDs & (1 << 2)) ? 'L' : 'G', Context->SegDs & 3);
        KdbpPrint("ES  0x%04x  Index 0x%04x  %cDT RPL%d\n",
                  Context->SegEs, Context->SegEs >> 3, (Context->SegEs & (1 << 2)) ? 'L' : 'G', Context->SegEs & 3);
        KdbpPrint("FS  0x%04x  Index 0x%04x  %cDT RPL%d\n",
                  Context->SegFs, Context->SegFs >> 3, (Context->SegFs & (1 << 2)) ? 'L' : 'G', Context->SegFs & 3);
        KdbpPrint("GS  0x%04x  Index 0x%04x  %cDT RPL%d\n",
                  Context->SegGs, Context->SegGs >> 3, (Context->SegGs & (1 << 2)) ? 'L' : 'G', Context->SegGs & 3);
        KdbpPrint("SS  0x%04x  Index 0x%04x  %cDT RPL%d\n",
                  Context->SegSs, Context->SegSs >> 3, (Context->SegSs & (1 << 2)) ? 'L' : 'G', Context->SegSs & 3);
    }
    else /* dregs */
    {
        ASSERT(Argv[0][0] == 'd');
        KdbpPrint("DR0  0x%08x\n"
                  "DR1  0x%08x\n"
                  "DR2  0x%08x\n"
                  "DR3  0x%08x\n"
                  "DR6  0x%08x\n"
                  "DR7  0x%08x\n",
                  Context->Dr0, Context->Dr1, Context->Dr2, Context->Dr3,
                  Context->Dr6, Context->Dr7);
    }

    return TRUE;
}

#ifdef _M_IX86
static PKTSS
KdbpRetrieveTss(
    IN USHORT TssSelector,
    OUT PULONG pType OPTIONAL,
    IN PKDESCRIPTOR pGdtr OPTIONAL)
{
    KDESCRIPTOR Gdtr;
    KGDTENTRY Desc;
    PKTSS Tss;

    /* Retrieve the Global Descriptor Table (user-provided or system) */
    if (pGdtr)
        Gdtr = *pGdtr;
    else
        Ke386GetGlobalDescriptorTable(&Gdtr.Limit);

    /* Check limits */
    if ((TssSelector & (sizeof(KGDTENTRY) - 1)) ||
        (TssSelector < sizeof(KGDTENTRY)) ||
        (TssSelector + sizeof(KGDTENTRY) - 1 > Gdtr.Limit))
    {
        return NULL;
    }

    /* Retrieve the descriptor */
    if (!NT_SUCCESS(KdbpSafeReadMemory(&Desc,
                                       (PVOID)(Gdtr.Base + TssSelector),
                                       sizeof(KGDTENTRY))))
    {
        return NULL;
    }

    /* Check for TSS32(Avl) or TSS32(Busy) */
    if (Desc.HighWord.Bits.Type != 9 && Desc.HighWord.Bits.Type != 11)
    {
        return NULL;
    }
    if (pType) *pType = Desc.HighWord.Bits.Type;

    Tss = (PKTSS)(ULONG_PTR)(Desc.BaseLow |
                             Desc.HighWord.Bytes.BaseMid << 16 |
                             Desc.HighWord.Bytes.BaseHi << 24);

    return Tss;
}

FORCEINLINE BOOLEAN
KdbpIsNestedTss(
    IN USHORT TssSelector,
    IN PKTSS Tss)
{
    USHORT Backlink;

    if (!Tss)
        return FALSE;

    /* Retrieve the TSS Backlink */
    if (!NT_SUCCESS(KdbpSafeReadMemory(&Backlink,
                                       (PVOID)&Tss->Backlink,
                                       sizeof(USHORT))))
    {
        return FALSE;
    }

    return (Backlink != 0 && Backlink != TssSelector);
}

static BOOLEAN
KdbpContextFromPrevTss(
    IN OUT PCONTEXT Context,
    OUT PUSHORT TssSelector,
    IN OUT PKTSS* pTss,
    IN PKDESCRIPTOR pGdtr)
{
    ULONG_PTR Eip, Ebp;
    USHORT Backlink;
    PKTSS Tss = *pTss;

    /* Retrieve the TSS Backlink */
    if (!NT_SUCCESS(KdbpSafeReadMemory(&Backlink,
                                       (PVOID)&Tss->Backlink,
                                       sizeof(USHORT))))
    {
        return FALSE;
    }

    /* Retrieve the parent TSS */
    Tss = KdbpRetrieveTss(Backlink, NULL, pGdtr);
    if (!Tss)
        return FALSE;

    if (!NT_SUCCESS(KdbpSafeReadMemory(&Eip,
                                       (PVOID)&Tss->Eip,
                                       sizeof(ULONG_PTR))))
    {
        return FALSE;
    }

    if (!NT_SUCCESS(KdbpSafeReadMemory(&Ebp,
                                       (PVOID)&Tss->Ebp,
                                       sizeof(ULONG_PTR))))
    {
        return FALSE;
    }

    /* Return the parent TSS and its trap frame */
    *TssSelector = Backlink;
    *pTss = Tss;
    Context->Eip = Eip;
    Context->Ebp = Ebp;
    return TRUE;
}
#endif

/*!\brief Displays a backtrace.
 */
static BOOLEAN
KdbpCmdBackTrace(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG ul;
    ULONGLONG Result = 0;
    CONTEXT Context = *KdbCurrentTrapFrame;
    ULONG_PTR Frame = KeGetContextFrameRegister(&Context);
    ULONG_PTR Address;

    if (Argc >= 2)
    {
        /* Check for [L count] part */
        ul = 0;
        if (strcmp(Argv[Argc-2], "L") == 0)
        {
            ul = strtoul(Argv[Argc-1], NULL, 0);
            if (ul > 0)
            {
                Argc -= 2;
            }
        }
        else if (Argv[Argc-1][0] == 'L')
        {
            ul = strtoul(Argv[Argc-1] + 1, NULL, 0);
            if (ul > 0)
            {
                Argc--;
            }
        }

        /* Put the remaining arguments back together */
        Argc--;
        for (ul = 1; ul < Argc; ul++)
        {
            Argv[ul][strlen(Argv[ul])] = ' ';
        }
        Argc++;
    }

    /* Check if a Frame Address or Thread ID is given */
    if (Argc > 1)
    {
        if (Argv[1][0] == '*')
        {
            Argv[1]++;

            /* Evaluate the expression */
            if (!KdbpEvaluateExpression(Argv[1], KdbPromptString.Length + (Argv[1]-Argv[0]), &Result))
                return TRUE;

            if (Result > (ULONGLONG)(~((ULONG_PTR)0)))
                KdbpPrint("Warning: Address %I64x is beeing truncated\n", Result);

            Frame = (ULONG_PTR)Result;
        }
        else
        {
            KdbpPrint("Thread backtrace not supported yet!\n");
            return TRUE;
        }
    }

#ifdef _M_IX86
    KDESCRIPTOR Gdtr;
    USHORT TssSelector;
    PKTSS Tss;

    /* Retrieve the Global Descriptor Table */
    Ke386GetGlobalDescriptorTable(&Gdtr.Limit);

    /* Retrieve the current (active) TSS */
    TssSelector = Ke386GetTr();
    Tss = KdbpRetrieveTss(TssSelector, NULL, &Gdtr);
    if (KdbpIsNestedTss(TssSelector, Tss))
    {
        /* Display the active TSS if it is nested */
        KdbpPrint("[Active TSS 0x%04x @ 0x%p]\n", TssSelector, Tss);
    }
#endif

    /* If no Frame Address or Thread ID was given, try printing the function at EIP */
    if (Argc <= 1)
    {
        KdbpPrint("Eip:\n");
        if (!KdbSymPrintAddress((PVOID)KeGetContextPc(&Context), &Context))
            KdbpPrint("<%p>\n", KeGetContextPc(&Context));
        else
            KdbpPrint("\n");
    }

    /* Walk through the frames */
    KdbpPrint("Frames:\n");
    for (;;)
    {
        BOOLEAN GotNextFrame;

        if (Frame == 0)
            goto CheckForParentTSS;

        Address = 0;
        if (!NT_SUCCESS(KdbpSafeReadMemory(&Address, (PVOID)(Frame + sizeof(ULONG_PTR)), sizeof(ULONG_PTR))))
        {
            KdbpPrint("Couldn't access memory at 0x%p!\n", Frame + sizeof(ULONG_PTR));
            goto CheckForParentTSS;
        }

        if (Address == 0)
            goto CheckForParentTSS;

        GotNextFrame = NT_SUCCESS(KdbpSafeReadMemory(&Frame, (PVOID)Frame, sizeof(ULONG_PTR)));
        if (GotNextFrame)
        {
            KeSetContextFrameRegister(&Context, Frame);
        }
        // else
            // Frame = 0;

        /* Print the location of the call instruction (assumed 5 bytes length) */
        if (!KdbSymPrintAddress((PVOID)(Address - 5), &Context))
            KdbpPrint("<%08x>\n", Address);
        else
            KdbpPrint("\n");

        if (KdbOutputAborted)
            break;

        if (!GotNextFrame)
        {
            KdbpPrint("Couldn't access memory at 0x%p!\n", Frame);
            goto CheckForParentTSS; // break;
        }

        continue;

CheckForParentTSS:
#ifndef _M_IX86
        break;
#else
        /*
         * We have ended the stack walking for the current (active) TSS.
         * Check whether this TSS was nested, and if so switch to its parent
         * and walk its stack.
         */
        if (!KdbpIsNestedTss(TssSelector, Tss))
            break; // The TSS is not nested, we stop there.

        GotNextFrame = KdbpContextFromPrevTss(&Context, &TssSelector, &Tss, &Gdtr);
        if (!GotNextFrame)
        {
            KdbpPrint("Couldn't access parent TSS 0x%04x\n", Tss->Backlink);
            break; // Cannot retrieve the parent TSS, we stop there.
        }


        Address = Context.Eip;
        Frame = Context.Ebp;

        KdbpPrint("[Parent TSS 0x%04x @ 0x%p]\n", TssSelector, Tss);

        if (!KdbSymPrintAddress((PVOID)Address, &Context))
            KdbpPrint("<%08x>\n", Address);
        else
            KdbpPrint("\n");
#endif
    }

    return TRUE;
}

/*!\brief Continues execution of the system/leaves KDB.
 */
static BOOLEAN
KdbpCmdContinue(
    ULONG Argc,
    PCHAR Argv[])
{
    /* Exit the main loop */
    return FALSE;
}

/*!\brief Continues execution of the system/leaves KDB.
 */
static BOOLEAN
KdbpCmdStep(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG Count = 1;

    if (Argc > 1)
    {
        Count = strtoul(Argv[1], NULL, 0);
        if (Count == 0)
        {
            KdbpPrint("%s: Integer argument required\n", Argv[0]);
            return TRUE;
        }
    }

    if (Argv[0][0] == 'n')
        KdbSingleStepOver = TRUE;
    else
        KdbSingleStepOver = FALSE;

    /* Set the number of single steps and return to the interrupted code. */
    KdbNumSingleSteps = Count;

    return FALSE;
}

/*!\brief Lists breakpoints.
 */
static BOOLEAN
KdbpCmdBreakPointList(
    ULONG Argc,
    PCHAR Argv[])
{
    LONG l;
    ULONG_PTR Address = 0;
    KDB_BREAKPOINT_TYPE Type = 0;
    KDB_ACCESS_TYPE AccessType = 0;
    UCHAR Size = 0;
    UCHAR DebugReg = 0;
    BOOLEAN Enabled = FALSE;
    BOOLEAN Global = FALSE;
    PEPROCESS Process = NULL;
    PCHAR str1, str2, ConditionExpr, GlobalOrLocal;
    CHAR Buffer[20];

    l = KdbpGetNextBreakPointNr(0);
    if (l < 0)
    {
        KdbpPrint("No breakpoints.\n");
        return TRUE;
    }

    KdbpPrint("Breakpoints:\n");
    do
    {
        if (!KdbpGetBreakPointInfo(l, &Address, &Type, &Size, &AccessType, &DebugReg,
                                   &Enabled, &Global, &Process, &ConditionExpr))
        {
            continue;
        }

        if (l == KdbLastBreakPointNr)
        {
            str1 = "\x1b[1m*";
            str2 = "\x1b[0m";
        }
        else
        {
            str1 = " ";
            str2 = "";
        }

        if (Global)
        {
            GlobalOrLocal = "  global";
        }
        else
        {
            GlobalOrLocal = Buffer;
            sprintf(Buffer, "  PID 0x%lx",
                    (ULONG_PTR)(Process ? Process->UniqueProcessId : INVALID_HANDLE_VALUE));
        }

        if (Type == KdbBreakPointSoftware || Type == KdbBreakPointTemporary)
        {
            KdbpPrint(" %s%03d  BPX  0x%08x%s%s%s%s%s\n",
                      str1, l, Address,
                      Enabled ? "" : "  disabled",
                      GlobalOrLocal,
                      ConditionExpr ? "  IF " : "",
                      ConditionExpr ? ConditionExpr : "",
                      str2);
        }
        else if (Type == KdbBreakPointHardware)
        {
            if (!Enabled)
            {
                KdbpPrint(" %s%03d  BPM  0x%08x  %-5s %-5s  disabled%s%s%s%s\n", str1, l, Address,
                          KDB_ACCESS_TYPE_TO_STRING(AccessType),
                          Size == 1 ? "byte" : (Size == 2 ? "word" : "dword"),
                          GlobalOrLocal,
                          ConditionExpr ? "  IF " : "",
                          ConditionExpr ? ConditionExpr : "",
                          str2);
            }
            else
            {
                KdbpPrint(" %s%03d  BPM  0x%08x  %-5s %-5s  DR%d%s%s%s%s\n", str1, l, Address,
                          KDB_ACCESS_TYPE_TO_STRING(AccessType),
                          Size == 1 ? "byte" : (Size == 2 ? "word" : "dword"),
                          DebugReg,
                          GlobalOrLocal,
                          ConditionExpr ? "  IF " : "",
                          ConditionExpr ? ConditionExpr : "",
                          str2);
            }
        }
    }
    while ((l = KdbpGetNextBreakPointNr(l+1)) >= 0);

    return TRUE;
}

/*!\brief Enables, disables or clears a breakpoint.
 */
static BOOLEAN
KdbpCmdEnableDisableClearBreakPoint(
    ULONG Argc,
    PCHAR Argv[])
{
    PCHAR pend;
    ULONG BreakPointNr;

    if (Argc < 2)
    {
        KdbpPrint("%s: argument required\n", Argv[0]);
        return TRUE;
    }

    pend = Argv[1];
    BreakPointNr = strtoul(Argv[1], &pend, 0);
    if (pend == Argv[1] || *pend != '\0')
    {
        KdbpPrint("%s: integer argument required\n", Argv[0]);
        return TRUE;
    }

    if (Argv[0][1] == 'e') /* enable */
    {
        KdbpEnableBreakPoint(BreakPointNr, NULL);
    }
    else if (Argv [0][1] == 'd') /* disable */
    {
        KdbpDisableBreakPoint(BreakPointNr, NULL);
    }
    else /* clear */
    {
        ASSERT(Argv[0][1] == 'c');
        KdbpDeleteBreakPoint(BreakPointNr, NULL);
    }

    return TRUE;
}

/*!\brief Sets a software or hardware (memory) breakpoint at the given address.
 */
static BOOLEAN
KdbpCmdBreakPoint(ULONG Argc, PCHAR Argv[])
{
    ULONGLONG Result = 0;
    ULONG_PTR Address;
    KDB_BREAKPOINT_TYPE Type;
    UCHAR Size = 0;
    KDB_ACCESS_TYPE AccessType = 0;
    ULONG AddressArgIndex, i;
    LONG ConditionArgIndex;
    BOOLEAN Global = TRUE;

    if (Argv[0][2] == 'x') /* software breakpoint */
    {
        if (Argc < 2)
        {
            KdbpPrint("bpx: Address argument required.\n");
            return TRUE;
        }

        AddressArgIndex = 1;
        Type = KdbBreakPointSoftware;
    }
    else /* memory breakpoint */
    {
        ASSERT(Argv[0][2] == 'm');

        if (Argc < 2)
        {
            KdbpPrint("bpm: Access type argument required (one of r, w, rw, x)\n");
            return TRUE;
        }

        if (_stricmp(Argv[1], "x") == 0)
            AccessType = KdbAccessExec;
        else if (_stricmp(Argv[1], "r") == 0)
            AccessType = KdbAccessRead;
        else if (_stricmp(Argv[1], "w") == 0)
            AccessType = KdbAccessWrite;
        else if (_stricmp(Argv[1], "rw") == 0)
            AccessType = KdbAccessReadWrite;
        else
        {
            KdbpPrint("bpm: Unknown access type '%s'\n", Argv[1]);
            return TRUE;
        }

        if (Argc < 3)
        {
            KdbpPrint("bpm: %s argument required.\n", AccessType == KdbAccessExec ? "Address" : "Memory size");
            return TRUE;
        }

        AddressArgIndex = 3;
        if (_stricmp(Argv[2], "byte") == 0)
            Size = 1;
        else if (_stricmp(Argv[2], "word") == 0)
            Size = 2;
        else if (_stricmp(Argv[2], "dword") == 0)
            Size = 4;
        else if (AccessType == KdbAccessExec)
        {
            Size = 1;
            AddressArgIndex--;
        }
        else
        {
            KdbpPrint("bpm: Unknown memory size '%s'\n", Argv[2]);
            return TRUE;
        }

        if (Argc <= AddressArgIndex)
        {
            KdbpPrint("bpm: Address argument required.\n");
            return TRUE;
        }

        Type = KdbBreakPointHardware;
    }

    /* Put the arguments back together */
    ConditionArgIndex = -1;
    for (i = AddressArgIndex; i < (Argc-1); i++)
    {
        if (strcmp(Argv[i+1], "IF") == 0) /* IF found */
        {
            ConditionArgIndex = i + 2;
            if ((ULONG)ConditionArgIndex >= Argc)
            {
                KdbpPrint("%s: IF requires condition expression.\n", Argv[0]);
                return TRUE;
            }

            for (i = ConditionArgIndex; i < (Argc-1); i++)
                Argv[i][strlen(Argv[i])] = ' ';

            break;
        }

        Argv[i][strlen(Argv[i])] = ' ';
    }

    /* Evaluate the address expression */
    if (!KdbpEvaluateExpression(Argv[AddressArgIndex],
                                KdbPromptString.Length + (Argv[AddressArgIndex]-Argv[0]),
                                &Result))
    {
        return TRUE;
    }

    if (Result > (ULONGLONG)(~((ULONG_PTR)0)))
        KdbpPrint("%s: Warning: Address %I64x is beeing truncated\n", Argv[0],Result);

    Address = (ULONG_PTR)Result;

    KdbpInsertBreakPoint(Address, Type, Size, AccessType,
                         (ConditionArgIndex < 0) ? NULL : Argv[ConditionArgIndex],
                         Global, NULL);

    return TRUE;
}

/*!\brief Lists threads or switches to another thread context.
 */
static BOOLEAN
KdbpCmdThread(
    ULONG Argc,
    PCHAR Argv[])
{
    PLIST_ENTRY Entry;
    PETHREAD Thread = NULL;
    PEPROCESS Process = NULL;
    BOOLEAN ReferencedThread = FALSE, ReferencedProcess = FALSE;
    PULONG_PTR Stack;
    PULONG_PTR Frame;
    ULONG_PTR Pc;
    ULONG_PTR ul = 0;
    PCHAR State, pend, str1, str2;
    static const PCHAR ThreadStateToString[DeferredReady+1] =
    {
        "Initialized", "Ready", "Running",
        "Standby", "Terminated", "Waiting",
        "Transition", "DeferredReady"
    };

    ASSERT(KdbCurrentProcess);

    if (Argc >= 2 && _stricmp(Argv[1], "list") == 0)
    {
        Process = KdbCurrentProcess;

        if (Argc >= 3)
        {
            ul = strtoulptr(Argv[2], &pend, 0);
            if (Argv[2] == pend)
            {
                KdbpPrint("thread: '%s' is not a valid process id!\n", Argv[2]);
                return TRUE;
            }

            if (!NT_SUCCESS(PsLookupProcessByProcessId((PVOID)ul, &Process)))
            {
                KdbpPrint("thread: Invalid process id!\n");
                return TRUE;
            }

            /* Remember our reference */
            ReferencedProcess = TRUE;
        }

        Entry = Process->ThreadListHead.Flink;
        if (Entry == &Process->ThreadListHead)
        {
            if (Argc >= 3)
                KdbpPrint("No threads in process 0x%px!\n", (PVOID)ul);
            else
                KdbpPrint("No threads in current process!\n");

            if (ReferencedProcess)
                ObDereferenceObject(Process);

            return TRUE;
        }

        KdbpPrint("  TID         State        Prior.  Affinity    EBP         EIP\n");
        do
        {
            Thread = CONTAINING_RECORD(Entry, ETHREAD, ThreadListEntry);

            if (Thread == KdbCurrentThread)
            {
                str1 = "\x1b[1m*";
                str2 = "\x1b[0m";
            }
            else
            {
                str1 = " ";
                str2 = "";
            }

            if (!Thread->Tcb.InitialStack)
            {
                /* Thread has no kernel stack (probably terminated) */
                Stack = Frame = NULL;
                Pc = 0;
            }
            else if (Thread->Tcb.TrapFrame)
            {
                Stack = (PULONG_PTR)KeGetTrapFrameStackRegister(Thread->Tcb.TrapFrame);
                Frame = (PULONG_PTR)KeGetTrapFrameFrameRegister(Thread->Tcb.TrapFrame);
                Pc = KeGetTrapFramePc(Thread->Tcb.TrapFrame);
            }
            else
            {
                Stack = (PULONG_PTR)Thread->Tcb.KernelStack;
                Frame = (PULONG_PTR)Stack[4];
                Pc = 0;

                if (Frame) /* FIXME: Should we attach to the process to read Ebp[1]? */
                    KdbpSafeReadMemory(&Pc, Frame + 1, sizeof(Pc));
            }

            if (Thread->Tcb.State < (DeferredReady + 1))
                State = ThreadStateToString[Thread->Tcb.State];
            else
                State = "Unknown";

            KdbpPrint(" %s0x%08x  %-11s  %3d     0x%08x  0x%08x  0x%08x%s\n",
                      str1,
                      Thread->Cid.UniqueThread,
                      State,
                      Thread->Tcb.Priority,
                      Thread->Tcb.Affinity,
                      Frame,
                      Pc,
                      str2);

            Entry = Entry->Flink;
        }
        while (Entry != &Process->ThreadListHead);

        /* Release our reference, if any */
        if (ReferencedProcess)
            ObDereferenceObject(Process);
    }
    else if (Argc >= 2 && _stricmp(Argv[1], "attach") == 0)
    {
        if (Argc < 3)
        {
            KdbpPrint("thread attach: thread id argument required!\n");
            return TRUE;
        }

        ul = strtoulptr(Argv[2], &pend, 0);
        if (Argv[2] == pend)
        {
            KdbpPrint("thread attach: '%s' is not a valid thread id!\n", Argv[2]);
            return TRUE;
        }

        if (!KdbpAttachToThread((PVOID)ul))
        {
            return TRUE;
        }

        KdbpPrint("Attached to thread 0x%08x.\n", ul);
    }
    else
    {
        Thread = KdbCurrentThread;

        if (Argc >= 2)
        {
            ul = strtoulptr(Argv[1], &pend, 0);
            if (Argv[1] == pend)
            {
                KdbpPrint("thread: '%s' is not a valid thread id!\n", Argv[1]);
                return TRUE;
            }

            if (!NT_SUCCESS(PsLookupThreadByThreadId((PVOID)ul, &Thread)))
            {
                KdbpPrint("thread: Invalid thread id!\n");
                return TRUE;
            }

            /* Remember our reference */
            ReferencedThread = TRUE;
        }

        if (Thread->Tcb.State < (DeferredReady + 1))
            State = ThreadStateToString[Thread->Tcb.State];
        else
            State = "Unknown";

        KdbpPrint("%s"
                  "  TID:            0x%08x\n"
                  "  State:          %s (0x%x)\n"
                  "  Priority:       %d\n"
                  "  Affinity:       0x%08x\n"
                  "  Initial Stack:  0x%08x\n"
                  "  Stack Limit:    0x%08x\n"
                  "  Stack Base:     0x%08x\n"
                  "  Kernel Stack:   0x%08x\n"
                  "  Trap Frame:     0x%08x\n"
#ifndef _M_AMD64
                  "  NPX State:      %s (0x%x)\n"
#endif
                  , (Argc < 2) ? "Current Thread:\n" : ""
                  , Thread->Cid.UniqueThread
                  , State, Thread->Tcb.State
                  , Thread->Tcb.Priority
                  , Thread->Tcb.Affinity
                  , Thread->Tcb.InitialStack
                  , Thread->Tcb.StackLimit
                  , Thread->Tcb.StackBase
                  , Thread->Tcb.KernelStack
                  , Thread->Tcb.TrapFrame
#ifndef _M_AMD64
                  , NPX_STATE_TO_STRING(Thread->Tcb.NpxState), Thread->Tcb.NpxState
#endif
            );

            /* Release our reference if we had one */
            if (ReferencedThread)
                ObDereferenceObject(Thread);
    }

    return TRUE;
}

/*!\brief Lists processes or switches to another process context.
 */
static BOOLEAN
KdbpCmdProc(
    ULONG Argc,
    PCHAR Argv[])
{
    PLIST_ENTRY Entry;
    PEPROCESS Process;
    BOOLEAN ReferencedProcess = FALSE;
    PCHAR State, pend, str1, str2;
    ULONG_PTR ul;
    extern LIST_ENTRY PsActiveProcessHead;

    if (Argc >= 2 && _stricmp(Argv[1], "list") == 0)
    {
        Entry = PsActiveProcessHead.Flink;
        if (!Entry || Entry == &PsActiveProcessHead)
        {
            KdbpPrint("No processes in the system!\n");
            return TRUE;
        }

        KdbpPrint("  PID         State       Filename\n");
        do
        {
            Process = CONTAINING_RECORD(Entry, EPROCESS, ActiveProcessLinks);

            if (Process == KdbCurrentProcess)
            {
                str1 = "\x1b[1m*";
                str2 = "\x1b[0m";
            }
            else
            {
                str1 = " ";
                str2 = "";
            }

            State = ((Process->Pcb.State == ProcessInMemory) ? "In Memory" :
                    ((Process->Pcb.State == ProcessOutOfMemory) ? "Out of Memory" : "In Transition"));

            KdbpPrint(" %s0x%08x  %-10s  %s%s\n",
                      str1,
                      Process->UniqueProcessId,
                      State,
                      Process->ImageFileName,
                      str2);

            Entry = Entry->Flink;
        }
        while(Entry != &PsActiveProcessHead);
    }
    else if (Argc >= 2 && _stricmp(Argv[1], "attach") == 0)
    {
        if (Argc < 3)
        {
            KdbpPrint("process attach: process id argument required!\n");
            return TRUE;
        }

        ul = strtoulptr(Argv[2], &pend, 0);
        if (Argv[2] == pend)
        {
            KdbpPrint("process attach: '%s' is not a valid process id!\n", Argv[2]);
            return TRUE;
        }

        if (!KdbpAttachToProcess((PVOID)ul))
        {
            return TRUE;
        }

        KdbpPrint("Attached to process 0x%p, thread 0x%p.\n", (PVOID)ul,
                  KdbCurrentThread->Cid.UniqueThread);
    }
    else
    {
        Process = KdbCurrentProcess;

        if (Argc >= 2)
        {
            ul = strtoulptr(Argv[1], &pend, 0);
            if (Argv[1] == pend)
            {
                KdbpPrint("proc: '%s' is not a valid process id!\n", Argv[1]);
                return TRUE;
            }

            if (!NT_SUCCESS(PsLookupProcessByProcessId((PVOID)ul, &Process)))
            {
                KdbpPrint("proc: Invalid process id!\n");
                return TRUE;
            }

            /* Remember our reference */
            ReferencedProcess = TRUE;
        }

        State = ((Process->Pcb.State == ProcessInMemory) ? "In Memory" :
                ((Process->Pcb.State == ProcessOutOfMemory) ? "Out of Memory" : "In Transition"));
        KdbpPrint("%s"
                  "  PID:             0x%08x\n"
                  "  State:           %s (0x%x)\n"
                  "  Image Filename:  %s\n",
                  (Argc < 2) ? "Current process:\n" : "",
                  Process->UniqueProcessId,
                  State, Process->Pcb.State,
                  Process->ImageFileName);

        /* Release our reference, if any */
        if (ReferencedProcess)
            ObDereferenceObject(Process);
    }

    return TRUE;
}

/*!\brief Lists loaded modules or the one containing the specified address.
 */
static BOOLEAN
KdbpCmdMod(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONGLONG Result = 0;
    ULONG_PTR Address;
    PLDR_DATA_TABLE_ENTRY LdrEntry;
    BOOLEAN DisplayOnlyOneModule = FALSE;
    INT i = 0;

    if (Argc >= 2)
    {
        /* Put the arguments back together */
        Argc--;
        while (--Argc >= 1)
            Argv[Argc][strlen(Argv[Argc])] = ' ';

        /* Evaluate the expression */
        if (!KdbpEvaluateExpression(Argv[1], KdbPromptString.Length + (Argv[1]-Argv[0]), &Result))
        {
            return TRUE;
        }

        if (Result > (ULONGLONG)(~((ULONG_PTR)0)))
            KdbpPrint("%s: Warning: Address %I64x is beeing truncated\n", Argv[0],Result);

        Address = (ULONG_PTR)Result;

        if (!KdbpSymFindModule((PVOID)Address, -1, &LdrEntry))
        {
            KdbpPrint("No module containing address 0x%p found!\n", Address);
            return TRUE;
        }

        DisplayOnlyOneModule = TRUE;
    }
    else
    {
        if (!KdbpSymFindModule(NULL, 0, &LdrEntry))
        {
            ULONG_PTR ntoskrnlBase = ((ULONG_PTR)KdbpCmdMod) & 0xfff00000;
            KdbpPrint("  Base      Size      Name\n");
            KdbpPrint("  %08x  %08x  %s\n", ntoskrnlBase, 0, "ntoskrnl.exe");
            return TRUE;
        }

        i = 1;
    }

    KdbpPrint("  Base      Size      Name\n");
    for (;;)
    {
        KdbpPrint("  %08x  %08x  %wZ\n", LdrEntry->DllBase, LdrEntry->SizeOfImage, &LdrEntry->BaseDllName);

        if(DisplayOnlyOneModule || !KdbpSymFindModule(NULL, i++, &LdrEntry))
            break;
    }

    return TRUE;
}

/*!\brief Displays GDT, LDT or IDT.
 */
static BOOLEAN
KdbpCmdGdtLdtIdt(
    ULONG Argc,
    PCHAR Argv[])
{
    KDESCRIPTOR Reg;
    ULONG SegDesc[2];
    ULONG SegBase;
    ULONG SegLimit;
    PCHAR SegType;
    USHORT SegSel;
    UCHAR Type, Dpl;
    INT i;
    ULONG ul;

    if (Argv[0][0] == 'i')
    {
        /* Read IDTR */
        __sidt(&Reg.Limit);

        if (Reg.Limit < 7)
        {
            KdbpPrint("Interrupt descriptor table is empty.\n");
            return TRUE;
        }

        KdbpPrint("IDT Base: 0x%08x  Limit: 0x%04x\n", Reg.Base, Reg.Limit);
        KdbpPrint("  Idx  Type        Seg. Sel.  Offset      DPL\n");

        for (i = 0; (i + sizeof(SegDesc) - 1) <= Reg.Limit; i += 8)
        {
            if (!NT_SUCCESS(KdbpSafeReadMemory(SegDesc, (PVOID)((ULONG_PTR)Reg.Base + i), sizeof(SegDesc))))
            {
                KdbpPrint("Couldn't access memory at 0x%p!\n", (PVOID)((ULONG_PTR)Reg.Base + i));
                return TRUE;
            }

            Dpl = ((SegDesc[1] >> 13) & 3);
            if ((SegDesc[1] & 0x1f00) == 0x0500)        /* Task gate */
                SegType = "TASKGATE";
            else if ((SegDesc[1] & 0x1fe0) == 0x0e00)   /* 32 bit Interrupt gate */
                SegType = "INTGATE32";
            else if ((SegDesc[1] & 0x1fe0) == 0x0600)   /* 16 bit Interrupt gate */
                SegType = "INTGATE16";
            else if ((SegDesc[1] & 0x1fe0) == 0x0f00)   /* 32 bit Trap gate */
                SegType = "TRAPGATE32";
            else if ((SegDesc[1] & 0x1fe0) == 0x0700)   /* 16 bit Trap gate */
                SegType = "TRAPGATE16";
            else
                SegType = "UNKNOWN";

            if ((SegDesc[1] & (1 << 15)) == 0) /* not present */
            {
                KdbpPrint("  %03d  %-10s  [NP]       [NP]        %02d\n",
                          i / 8, SegType, Dpl);
            }
            else if ((SegDesc[1] & 0x1f00) == 0x0500) /* Task gate */
            {
                SegSel = SegDesc[0] >> 16;
                KdbpPrint("  %03d  %-10s  0x%04x                 %02d\n",
                          i / 8, SegType, SegSel, Dpl);
            }
            else
            {
                SegSel = SegDesc[0] >> 16;
                SegBase = (SegDesc[1] & 0xffff0000) | (SegDesc[0] & 0x0000ffff);
                KdbpPrint("  %03d  %-10s  0x%04x     0x%08x  %02d\n",
                          i / 8, SegType, SegSel, SegBase, Dpl);
            }
        }
    }
    else
    {
        ul = 0;

        if (Argv[0][0] == 'g')
        {
            /* Read GDTR */
            Ke386GetGlobalDescriptorTable(&Reg.Limit);
            i = 8;
        }
        else
        {
            ASSERT(Argv[0][0] == 'l');

            /* Read LDTR */
            Ke386GetLocalDescriptorTable(&Reg.Limit);
            Reg.Base = 0;
            i = 0;
            ul = 1 << 2;
        }

        if (Reg.Limit < 7)
        {
            KdbpPrint("%s descriptor table is empty.\n",
                      Argv[0][0] == 'g' ? "Global" : "Local");
            return TRUE;
        }

        KdbpPrint("%cDT Base: 0x%08x  Limit: 0x%04x\n",
                  Argv[0][0] == 'g' ? 'G' : 'L', Reg.Base, Reg.Limit);
        KdbpPrint("  Idx  Sel.    Type         Base        Limit       DPL  Attribs\n");

        for (; (i + sizeof(SegDesc) - 1) <= Reg.Limit; i += 8)
        {
            if (!NT_SUCCESS(KdbpSafeReadMemory(SegDesc, (PVOID)((ULONG_PTR)Reg.Base + i), sizeof(SegDesc))))
            {
                KdbpPrint("Couldn't access memory at 0x%p!\n", (ULONG_PTR)Reg.Base + i);
                return TRUE;
            }

            Dpl = ((SegDesc[1] >> 13) & 3);
            Type = ((SegDesc[1] >> 8) & 0xf);

            SegBase = SegDesc[0] >> 16;
            SegBase |= (SegDesc[1] & 0xff) << 16;
            SegBase |= SegDesc[1] & 0xff000000;
            SegLimit = SegDesc[0] & 0x0000ffff;
            SegLimit |= (SegDesc[1] >> 16) & 0xf;

            if ((SegDesc[1] & (1 << 23)) != 0)
            {
                SegLimit *= 4096;
                SegLimit += 4095;
            }
            else
            {
                SegLimit++;
            }

            if ((SegDesc[1] & (1 << 12)) == 0) /* System segment */
            {
                switch (Type)
                {
                    case  1: SegType = "TSS16(Avl)";    break;
                    case  2: SegType = "LDT";           break;
                    case  3: SegType = "TSS16(Busy)";   break;
                    case  4: SegType = "CALLGATE16";    break;
                    case  5: SegType = "TASKGATE";      break;
                    case  6: SegType = "INTGATE16";     break;
                    case  7: SegType = "TRAPGATE16";    break;
                    case  9: SegType = "TSS32(Avl)";    break;
                    case 11: SegType = "TSS32(Busy)";   break;
                    case 12: SegType = "CALLGATE32";    break;
                    case 14: SegType = "INTGATE32";     break;
                    case 15: SegType = "TRAPGATE32";    break;
                    default: SegType = "UNKNOWN";       break;
                }

                if (!(Type >= 1 && Type <= 3) &&
                    Type != 9 && Type != 11)
                {
                    SegBase = 0;
                    SegLimit = 0;
                }
            }
            else if ((SegDesc[1] & (1 << 11)) == 0) /* Data segment */
            {
                if ((SegDesc[1] & (1 << 22)) != 0)
                    SegType = "DATA32";
                else
                    SegType = "DATA16";
            }
            else /* Code segment */
            {
                if ((SegDesc[1] & (1 << 22)) != 0)
                    SegType = "CODE32";
                else
                    SegType = "CODE16";
            }

            if ((SegDesc[1] & (1 << 15)) == 0) /* Not present */
            {
                KdbpPrint("  %03d  0x%04x  %-11s  [NP]        [NP]        %02d   NP\n",
                          i / 8, i | Dpl | ul, SegType, Dpl);
            }
            else
            {
                KdbpPrint("  %03d  0x%04x  %-11s  0x%08x  0x%08x  %02d  ",
                          i / 8, i | Dpl | ul, SegType, SegBase, SegLimit, Dpl);

                if ((SegDesc[1] & (1 << 12)) == 0) /* System segment */
                {
                    /* FIXME: Display system segment */
                }
                else if ((SegDesc[1] & (1 << 11)) == 0) /* Data segment */
                {
                    if ((SegDesc[1] & (1 << 10)) != 0) /* Expand-down */
                        KdbpPrint(" E");

                    KdbpPrint((SegDesc[1] & (1 << 9)) ? " R/W" : " R");

                    if ((SegDesc[1] & (1 << 8)) != 0)
                        KdbpPrint(" A");
                }
                else /* Code segment */
                {
                    if ((SegDesc[1] & (1 << 10)) != 0) /* Conforming */
                        KdbpPrint(" C");

                    KdbpPrint((SegDesc[1] & (1 << 9)) ? " R/X" : " X");

                    if ((SegDesc[1] & (1 << 8)) != 0)
                        KdbpPrint(" A");
                }

                if ((SegDesc[1] & (1 << 20)) != 0)
                    KdbpPrint(" AVL");

                KdbpPrint("\n");
            }
        }
    }

    return TRUE;
}

/*!\brief Displays the KPCR
 */
static BOOLEAN
KdbpCmdPcr(
    ULONG Argc,
    PCHAR Argv[])
{
    PKIPCR Pcr = (PKIPCR)KeGetPcr();

    KdbpPrint("Current PCR is at 0x%p.\n", Pcr);
    KdbpPrint("  Tib.ExceptionList:         0x%08x\n"
              "  Tib.StackBase:             0x%08x\n"
              "  Tib.StackLimit:            0x%08x\n"
              "  Tib.SubSystemTib:          0x%08x\n"
              "  Tib.FiberData/Version:     0x%08x\n"
              "  Tib.ArbitraryUserPointer:  0x%08x\n"
              "  Tib.Self:                  0x%08x\n"
#ifdef _M_IX86
              "  SelfPcr:                   0x%08x\n"
#else
              "  Self:                      0x%p\n"
#endif
              "  PCRCB:                     0x%08x\n"
              "  Irql:                      0x%02x\n"
#ifdef _M_IX86
              "  IRR:                       0x%08x\n"
              "  IrrActive:                 0x%08x\n"
              "  IDR:                       0x%08x\n"
#endif
              "  KdVersionBlock:            0x%08x\n"
#ifdef _M_IX86
              "  IDT:                       0x%08x\n"
              "  GDT:                       0x%08x\n"
              "  TSS:                       0x%08x\n"
#endif
              "  MajorVersion:              0x%04x\n"
              "  MinorVersion:              0x%04x\n"
#ifdef _M_IX86
              "  SetMember:                 0x%08x\n"
#endif
              "  StallScaleFactor:          0x%08x\n"
#ifdef _M_IX86
              "  Number:                    0x%02x\n"
#endif
              "  L2CacheAssociativity:      0x%02x\n"
#ifdef _M_IX86
              "  VdmAlert:                  0x%08x\n"
#endif
              "  L2CacheSize:               0x%08x\n"
#ifdef _M_IX86
              "  InterruptMode:             0x%08x\n"
#endif
              , Pcr->NtTib.ExceptionList, Pcr->NtTib.StackBase, Pcr->NtTib.StackLimit,
              Pcr->NtTib.SubSystemTib, Pcr->NtTib.FiberData, Pcr->NtTib.ArbitraryUserPointer,
              Pcr->NtTib.Self
#ifdef _M_IX86
              , Pcr->SelfPcr
#else
              , Pcr->Self
#endif
              , Pcr->Prcb, Pcr->Irql
#ifdef _M_IX86
              , Pcr->IRR, Pcr->IrrActive , Pcr->IDR
#endif
              , Pcr->KdVersionBlock
#ifdef _M_IX86
              , Pcr->IDT, Pcr->GDT, Pcr->TSS
#endif
              , Pcr->MajorVersion, Pcr->MinorVersion
#ifdef _M_IX86
              , Pcr->SetMember
#endif
              , Pcr->StallScaleFactor
#ifdef _M_IX86
              , Pcr->Number
#endif
              , Pcr->SecondLevelCacheAssociativity
#ifdef _M_IX86
              , Pcr->VdmAlert
#endif
              , Pcr->SecondLevelCacheSize
#ifdef _M_IX86
              , Pcr->InterruptMode
#endif
              );


    return TRUE;
}

#ifdef _M_IX86
/*!\brief Displays the TSS
 */
static BOOLEAN
KdbpCmdTss(
    ULONG Argc,
    PCHAR Argv[])
{
    USHORT TssSelector;
    PKTSS Tss = NULL;

    if (Argc >= 2)
    {
        /*
         * Specified TSS via its selector [selector] or descriptor address [*descaddr].
         * Note that we ignore any other argument values.
         */
        PCHAR Param, pszNext;
        ULONG ulValue;

        Param = Argv[1];
        if (Argv[1][0] == '*')
            ++Param;

        ulValue = strtoul(Param, &pszNext, 0);
        if (pszNext && *pszNext)
        {
            KdbpPrint("Invalid TSS specification.\n");
            return TRUE;
        }

        if (Argv[1][0] == '*')
        {
            /* Descriptor specified */
            TssSelector = 0; // Unknown selector!
            // TODO: Room for improvement: Find the TSS descriptor
            // in the GDT so as to validate it.
            Tss = (PKTSS)(ULONG_PTR)ulValue;
            if (!Tss)
            {
                KdbpPrint("Invalid 32-bit TSS descriptor.\n");
                return TRUE;
            }
        }
        else
        {
            /* Selector specified, retrive the corresponding TSS */
            TssSelector = (USHORT)ulValue;
            Tss = KdbpRetrieveTss(TssSelector, NULL, NULL);
            if (!Tss)
            {
                KdbpPrint("Invalid 32-bit TSS selector.\n");
                return TRUE;
            }
        }
    }

    if (!Tss)
    {
        /* If no TSS was specified, use the current TSS descriptor */
        TssSelector = Ke386GetTr();
        Tss = KeGetPcr()->TSS;
        // NOTE: If everything works OK, Tss is the current TSS corresponding to the TR selector.
    }

    KdbpPrint("%s TSS 0x%04x is at 0x%p.\n",
              (Tss == KeGetPcr()->TSS) ? "Current" : "Specified", TssSelector, Tss);
    KdbpPrint("  Backlink:  0x%04x\n"
              "  Ss0:Esp0:  0x%04x:0x%08x\n"
              // NOTE: Ss1:Esp1 and Ss2:Esp2: are in the NotUsed1 field.
              "  CR3:       0x%08x\n"
              "  EFlags:    0x%08x\n"
              "  Eax:       0x%08x\n"
              "  Ebx:       0x%08x\n"
              "  Ecx:       0x%08x\n"
              "  Edx:       0x%08x\n"
              "  Esi:       0x%08x\n"
              "  Edi:       0x%08x\n"
              "  Eip:       0x%08x\n"
              "  Esp:       0x%08x\n"
              "  Ebp:       0x%08x\n"
              "  Cs:        0x%04x\n"
              "  Ss:        0x%04x\n"
              "  Ds:        0x%04x\n"
              "  Es:        0x%04x\n"
              "  Fs:        0x%04x\n"
              "  Gs:        0x%04x\n"
              "  LDT:       0x%04x\n"
              "  Flags:     0x%04x\n"
              "  IoMapBase: 0x%04x\n",
              Tss->Backlink, Tss->Ss0, Tss->Esp0, Tss->CR3, Tss->EFlags,
              Tss->Eax, Tss->Ebx, Tss->Ecx, Tss->Edx, Tss->Esi, Tss->Edi,
              Tss->Eip, Tss->Esp, Tss->Ebp,
              Tss->Cs, Tss->Ss, Tss->Ds, Tss->Es, Tss->Fs, Tss->Gs,
              Tss->LDT, Tss->Flags, Tss->IoMapBase);

    return TRUE;
}
#endif

/*!\brief Bugchecks the system.
 */
static BOOLEAN
KdbpCmdBugCheck(
    ULONG Argc,
    PCHAR Argv[])
{
    /* Set the flag and quit looping */
    KdbpBugCheckRequested = TRUE;
    return FALSE;
}

static BOOLEAN
KdbpCmdReboot(
    ULONG Argc,
    PCHAR Argv[])
{
    /* Reboot immediately (we do not return) */
    HalReturnToFirmware(HalRebootRoutine);
    return FALSE;
}


VOID
KdbpPager(
    IN PCHAR Buffer,
    IN ULONG BufLength);

/*!\brief Display debug messages on screen, with paging.
 *
 * Keys for per-page view: Home, End, PageUp, Arrow Up, PageDown,
 * all others are as PageDown.
 */
static BOOLEAN
KdbpCmdDmesg(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG beg, end;

    KdbpIsInDmesgMode = TRUE; /* Toggle logging flag */
    if (!KdpDmesgBuffer)
    {
        KdbpPrint("Dmesg: error, buffer is not allocated! /DEBUGPORT=SCREEN kernel param required for dmesg.\n");
        return TRUE;
    }

    KdbpPrint("*** Dmesg *** TotalWritten=%lu, BufferSize=%lu, CurrentPosition=%lu\n",
              KdbDmesgTotalWritten, KdpDmesgBufferSize, KdpDmesgCurrentPosition);

    /* Pass data to the pager */
    end = KdpDmesgCurrentPosition;
    beg = (end + KdpDmesgFreeBytes) % KdpDmesgBufferSize;

    /* No roll-overs, and overwritten=lost bytes */
    if (KdbDmesgTotalWritten <= KdpDmesgBufferSize)
    {
        /* Show buffer (KdpDmesgBuffer + beg, num) */
        KdbpPager(KdpDmesgBuffer, KdpDmesgCurrentPosition);
    }
    else
    {
        /* Show 2 buffers: (KdpDmesgBuffer + beg, KdpDmesgBufferSize - beg)
         *            and: (KdpDmesgBuffer,       end) */
        KdbpPager(KdpDmesgBuffer + beg, KdpDmesgBufferSize - beg);
        KdbpPrint("*** Dmesg: buffer rollup ***\n");
        KdbpPager(KdpDmesgBuffer,       end);
    }
    KdbpPrint("*** Dmesg: end of output ***\n");

    KdbpIsInDmesgMode = FALSE; /* Toggle logging flag */

    return TRUE;
}

/*!\brief Sets or displays a config variables value.
 */
static BOOLEAN
KdbpCmdSet(
    ULONG Argc,
    PCHAR Argv[])
{
    LONG l;
    BOOLEAN First;
    PCHAR pend = 0;
    KDB_ENTER_CONDITION ConditionFirst = KdbDoNotEnter;
    KDB_ENTER_CONDITION ConditionLast = KdbDoNotEnter;

    static const PCHAR ExceptionNames[21] =
    {
        "ZERODEVIDE", "DEBUGTRAP", "NMI", "INT3", "OVERFLOW", "BOUND", "INVALIDOP",
        "NOMATHCOP", "DOUBLEFAULT", "RESERVED(9)", "INVALIDTSS", "SEGMENTNOTPRESENT",
        "STACKFAULT", "GPF", "PAGEFAULT", "RESERVED(15)", "MATHFAULT", "ALIGNMENTCHECK",
        "MACHINECHECK", "SIMDFAULT", "OTHERS"
    };

    if (Argc == 1)
    {
        KdbpPrint("Available settings:\n");
        KdbpPrint("  syntax [intel|at&t]\n");
        KdbpPrint("  condition [exception|*] [first|last] [never|always|kmode|umode]\n");
        KdbpPrint("  break_on_module_load [true|false]\n");
    }
    else if (strcmp(Argv[1], "syntax") == 0)
    {
        if (Argc == 2)
        {
            KdbpPrint("syntax = %s\n", KdbUseIntelSyntax ? "intel" : "at&t");
        }
        else if (Argc >= 3)
        {
            if (_stricmp(Argv[2], "intel") == 0)
                KdbUseIntelSyntax = TRUE;
            else if (_stricmp(Argv[2], "at&t") == 0)
                KdbUseIntelSyntax = FALSE;
            else
                KdbpPrint("Unknown syntax '%s'.\n", Argv[2]);
        }
    }
    else if (strcmp(Argv[1], "condition") == 0)
    {
        if (Argc == 2)
        {
            KdbpPrint("Conditions:                 (First)  (Last)\n");
            for (l = 0; l < RTL_NUMBER_OF(ExceptionNames) - 1; l++)
            {
                if (!ExceptionNames[l])
                    continue;

                if (!KdbpGetEnterCondition(l, TRUE, &ConditionFirst))
                    ASSERT(FALSE);

                if (!KdbpGetEnterCondition(l, FALSE, &ConditionLast))
                    ASSERT(FALSE);

                KdbpPrint("  #%02d  %-20s %-8s %-8s\n", l, ExceptionNames[l],
                          KDB_ENTER_CONDITION_TO_STRING(ConditionFirst),
                          KDB_ENTER_CONDITION_TO_STRING(ConditionLast));
            }

            ASSERT(l == (RTL_NUMBER_OF(ExceptionNames) - 1));
            KdbpPrint("       %-20s %-8s %-8s\n", ExceptionNames[l],
                      KDB_ENTER_CONDITION_TO_STRING(ConditionFirst),
                      KDB_ENTER_CONDITION_TO_STRING(ConditionLast));
        }
        else
        {
            if (Argc >= 5 && strcmp(Argv[2], "*") == 0) /* Allow * only when setting condition */
            {
                l = -1;
            }
            else
            {
                l = strtoul(Argv[2], &pend, 0);

                if (Argv[2] == pend)
                {
                    for (l = 0; l < RTL_NUMBER_OF(ExceptionNames); l++)
                    {
                        if (!ExceptionNames[l])
                            continue;

                        if (_stricmp(ExceptionNames[l], Argv[2]) == 0)
                            break;
                    }
                }

                if (l >= RTL_NUMBER_OF(ExceptionNames))
                {
                    KdbpPrint("Unknown exception '%s'.\n", Argv[2]);
                    return TRUE;
                }
            }

            if (Argc > 4)
            {
                if (_stricmp(Argv[3], "first") == 0)
                    First = TRUE;
                else if (_stricmp(Argv[3], "last") == 0)
                    First = FALSE;
                else
                {
                    KdbpPrint("set condition: second argument must be 'first' or 'last'\n");
                    return TRUE;
                }

                if (_stricmp(Argv[4], "never") == 0)
                    ConditionFirst = KdbDoNotEnter;
                else if (_stricmp(Argv[4], "always") == 0)
                    ConditionFirst = KdbEnterAlways;
                else if (_stricmp(Argv[4], "umode") == 0)
                    ConditionFirst = KdbEnterFromUmode;
                else if (_stricmp(Argv[4], "kmode") == 0)
                    ConditionFirst = KdbEnterFromKmode;
                else
                {
                    KdbpPrint("set condition: third argument must be 'never', 'always', 'umode' or 'kmode'\n");
                    return TRUE;
                }

                if (!KdbpSetEnterCondition(l, First, ConditionFirst))
                {
                    if (l >= 0)
                        KdbpPrint("Couldn't change condition for exception #%02d\n", l);
                    else
                        KdbpPrint("Couldn't change condition for all exceptions\n", l);
                }
            }
            else /* Argc >= 3 */
            {
                if (!KdbpGetEnterCondition(l, TRUE, &ConditionFirst))
                    ASSERT(FALSE);

                if (!KdbpGetEnterCondition(l, FALSE, &ConditionLast))
                    ASSERT(FALSE);

                if (l < (RTL_NUMBER_OF(ExceptionNames) - 1))
                {
                    KdbpPrint("Condition for exception #%02d (%s): FirstChance %s  LastChance %s\n",
                              l, ExceptionNames[l],
                              KDB_ENTER_CONDITION_TO_STRING(ConditionFirst),
                              KDB_ENTER_CONDITION_TO_STRING(ConditionLast));
                }
                else
                {
                    KdbpPrint("Condition for all other exceptions: FirstChance %s  LastChance %s\n",
                              KDB_ENTER_CONDITION_TO_STRING(ConditionFirst),
                              KDB_ENTER_CONDITION_TO_STRING(ConditionLast));
                }
            }
        }
    }
    else if (strcmp(Argv[1], "break_on_module_load") == 0)
    {
        if (Argc == 2)
            KdbpPrint("break_on_module_load = %s\n", KdbBreakOnModuleLoad ? "enabled" : "disabled");
        else if (Argc >= 3)
        {
            if (_stricmp(Argv[2], "enable") == 0 || _stricmp(Argv[2], "enabled") == 0 || _stricmp(Argv[2], "true") == 0)
                KdbBreakOnModuleLoad = TRUE;
            else if (_stricmp(Argv[2], "disable") == 0 || _stricmp(Argv[2], "disabled") == 0 || _stricmp(Argv[2], "false") == 0)
                KdbBreakOnModuleLoad = FALSE;
            else
                KdbpPrint("Unknown setting '%s'.\n", Argv[2]);
        }
    }
    else
    {
        KdbpPrint("Unknown setting '%s'.\n", Argv[1]);
    }

    return TRUE;
}

/*!\brief Displays help screen.
 */
static BOOLEAN
KdbpCmdHelp(
    ULONG Argc,
    PCHAR Argv[])
{
    ULONG i;

    KdbpPrint("Kernel debugger commands:\n");
    for (i = 0; i < RTL_NUMBER_OF(KdbDebuggerCommands); i++)
    {
        if (!KdbDebuggerCommands[i].Syntax) /* Command group */
        {
            if (i > 0)
                KdbpPrint("\n");

            KdbpPrint("\x1b[7m* %s:\x1b[0m\n", KdbDebuggerCommands[i].Help);
            continue;
        }

        KdbpPrint("  %-20s - %s\n",
                  KdbDebuggerCommands[i].Syntax,
                  KdbDebuggerCommands[i].Help);
    }

    return TRUE;
}

/*!\brief Prints the given string with printf-like formatting.
 *
 * \param Format  Format of the string/arguments.
 * \param ...     Variable number of arguments matching the format specified in \a Format.
 *
 * \note Doesn't correctly handle \\t and terminal escape sequences when calculating the
 *       number of lines required to print a single line from the Buffer in the terminal.
 *       Prints maximum 4096 chars, because of its buffer size.
 *       Uses KdpDPrintf internally (NOT DbgPrint!). Callers must already hold the debugger lock.
 */
VOID
KdbpPrint(
    IN PCHAR Format,
    IN ...  OPTIONAL)
{
    static CHAR Buffer[4096];
    static BOOLEAN TerminalInitialized = FALSE;
    static BOOLEAN TerminalConnected = FALSE;
    static BOOLEAN TerminalReportsSize = TRUE;
    CHAR c = '\0';
    PCHAR p, p2;
    ULONG Length;
    ULONG i, j;
    LONG RowsPrintedByTerminal;
    ULONG ScanCode;
    va_list ap;

    /* Check if the user has aborted output of the current command */
    if (KdbOutputAborted)
        return;

    /* Initialize the terminal */
    if (!TerminalInitialized)
    {
        KdpDprintf("\x1b[7h");      /* Enable linewrap */

        /* Query terminal type */
        /*DbgPrint("\x1b[Z");*/
        KdpDprintf("\x05");

        TerminalInitialized = TRUE;
        Length = 0;
        KeStallExecutionProcessor(100000);

        for (;;)
        {
            c = KdbpTryGetCharSerial(5000);
            if (c == -1)
                break;

            Buffer[Length++] = c;
            if (Length >= (sizeof(Buffer) - 1))
                break;
        }

        Buffer[Length] = '\0';
        if (Length > 0)
            TerminalConnected = TRUE;
    }

    /* Get number of rows and columns in terminal */
    if ((KdbNumberOfRowsTerminal < 0) || (KdbNumberOfColsTerminal < 0) ||
        (KdbNumberOfRowsPrinted) == 0) /* Refresh terminal size each time when number of rows printed is 0 */
    {
        if ((KdbDebugState & KD_DEBUG_KDSERIAL) && TerminalConnected && TerminalReportsSize)
        {
            /* Try to query number of rows from terminal. A reply looks like "\x1b[8;24;80t" */
            TerminalReportsSize = FALSE;
            KeStallExecutionProcessor(100000);
            KdpDprintf("\x1b[18t");
            c = KdbpTryGetCharSerial(5000);

            if (c == KEY_ESC)
            {
                c = KdbpTryGetCharSerial(5000);
                if (c == '[')
                {
                    Length = 0;

                    for (;;)
                    {
                        c = KdbpTryGetCharSerial(5000);
                        if (c == -1)
                            break;

                        Buffer[Length++] = c;
                        if (isalpha(c) || Length >= (sizeof(Buffer) - 1))
                            break;
                    }

                    Buffer[Length] = '\0';
                    if (Buffer[0] == '8' && Buffer[1] == ';')
                    {
                        for (i = 2; (i < Length) && (Buffer[i] != ';'); i++);

                        if (Buffer[i] == ';')
                        {
                            Buffer[i++] = '\0';

                            /* Number of rows is now at Buffer + 2 and number of cols at Buffer + i */
                            KdbNumberOfRowsTerminal = strtoul(Buffer + 2, NULL, 0);
                            KdbNumberOfColsTerminal = strtoul(Buffer + i, NULL, 0);
                            TerminalReportsSize = TRUE;
                        }
                    }
                }
                /* Clear further characters */
                while ((c = KdbpTryGetCharSerial(5000)) != -1);
            }
        }

        if (KdbNumberOfRowsTerminal <= 0)
        {
            /* Set number of rows to the default. */
            KdbNumberOfRowsTerminal = 23; //24; //Mna.: 23 for SCREEN debugport
        }
        else if (KdbNumberOfColsTerminal <= 0)
        {
            /* Set number of cols to the default. */
            KdbNumberOfColsTerminal = 75; //80; //Mna.: 75 for SCREEN debugport
        }
    }

    /* Get the string */
    va_start(ap, Format);
    Length = _vsnprintf(Buffer, sizeof(Buffer) - 1, Format, ap);
    Buffer[Length] = '\0';
    va_end(ap);

    p = Buffer;
    while (p[0] != '\0')
    {
        i = strcspn(p, "\n");

        /* Calculate the number of lines which will be printed in the terminal
         * when outputting the current line
         */
        if (i > 0)
            RowsPrintedByTerminal = (i + KdbNumberOfColsPrinted - 1) / KdbNumberOfColsTerminal;
        else
            RowsPrintedByTerminal = 0;

        if (p[i] == '\n')
            RowsPrintedByTerminal++;

        /*DbgPrint("!%d!%d!%d!%d!", KdbNumberOfRowsPrinted, KdbNumberOfColsPrinted, i, RowsPrintedByTerminal);*/

        /* Display a prompt if we printed one screen full of text */
        if (KdbNumberOfRowsTerminal > 0 &&
            (LONG)(KdbNumberOfRowsPrinted + RowsPrintedByTerminal) >= KdbNumberOfRowsTerminal)
        {
            KdbRepeatLastCommand = FALSE;

            if (KdbNumberOfColsPrinted > 0)
                KdpDprintf("\n");

            KdpDprintf("--- Press q to abort, any other key to continue ---");
            RowsPrintedByTerminal++; /* added by Mna. */

            if (KdbDebugState & KD_DEBUG_KDSERIAL)
                c = KdbpGetCharSerial();
            else
                c = KdbpGetCharKeyboard(&ScanCode);

            if (c == '\r')
            {
                /* Try to read '\n' which might follow '\r' - if \n is not received here
                 * it will be interpreted as "return" when the next command should be read.
                 */
                if (KdbDebugState & KD_DEBUG_KDSERIAL)
                    c = KdbpTryGetCharSerial(5);
                else
                    c = KdbpTryGetCharKeyboard(&ScanCode, 5);
            }

            KdpDprintf("\n");
            if (c == 'q')
            {
                KdbOutputAborted = TRUE;
                return;
            }

            KdbNumberOfRowsPrinted = 0;
            KdbNumberOfColsPrinted = 0;
        }

        /* Insert a NUL after the line and print only the current line. */
        if (p[i] == '\n' && p[i + 1] != '\0')
        {
            c = p[i + 1];
            p[i + 1] = '\0';
        }
        else
        {
            c = '\0';
        }

        /* Remove escape sequences from the line if there's no terminal connected */
        if (!TerminalConnected)
        {
            while ((p2 = strrchr(p, '\x1b'))) /* Look for escape character */
            {
                size_t len = strlen(p2);
                if (p2[1] == '[')
                {
                    j = 2;
                    while (!isalpha(p2[j++]));
                    memmove(p2, p2 + j, len + 1 - j);
                }
                else
                {
                    memmove(p2, p2 + 1, len);
                }
            }
        }

        KdpDprintf("%s", p);

        if (c != '\0')
            p[i + 1] = c;

        /* Set p to the start of the next line and
         * remember the number of rows/cols printed
         */
        p += i;
        if (p[0] == '\n')
        {
            p++;
            KdbNumberOfColsPrinted = 0;
        }
        else
        {
            ASSERT(p[0] == '\0');
            KdbNumberOfColsPrinted += i;
        }

        KdbNumberOfRowsPrinted += RowsPrintedByTerminal;
    }
}

/** memrchr(), explicitly defined, since was absent in MinGW of RosBE. */
/*
 * Reverse memchr()
 * Find the last occurrence of 'c' in the buffer 's' of size 'n'.
 */
void *
memrchr(const void *s, int c, size_t n)
{
    const unsigned char *cp;

    if (n != 0)
    {
        cp = (unsigned char *)s + n;
        do
        {
            if (*(--cp) == (unsigned char)c)
                return (void *)cp;
        } while (--n != 0);
    }
    return NULL;
}

/*!\brief Calculate pointer position for N lines upper of current position.
 *
 * \param Buffer     Characters buffer to operate on.
 * \param BufLength  Buffer size.
 *
 * \note Calculate pointer position for N lines upper of current displaying
 *       position within the given buffer.
 *
 * Used by KdbpPager().
 * Now N lines count is hardcoded to KdbNumberOfRowsTerminal.
 */
PCHAR
CountOnePageUp(PCHAR Buffer, ULONG BufLength, PCHAR pCurPos)
{
    PCHAR p;
    // p0 is initial guess of Page Start
    ULONG p0len = KdbNumberOfRowsTerminal * KdbNumberOfColsTerminal;
    PCHAR p0 = pCurPos - p0len;
    PCHAR prev_p = p0, p1;
    ULONG j;

    if (pCurPos < Buffer)
        pCurPos = Buffer;
    ASSERT(pCurPos <= Buffer + BufLength);

    p = memrchr(p0, '\n', p0len);
    if (NULL == p)
        p = p0;
    for (j = KdbNumberOfRowsTerminal; j--; )
    {
        int linesCnt;
        p1 = memrchr(p0, '\n', p-p0);
        prev_p = p;
        p = p1;
        if (NULL == p)
        {
            p = prev_p;
            if (NULL == p)
                p = p0;
            break;
        }
        linesCnt = (KdbNumberOfColsTerminal+prev_p-p-2) / KdbNumberOfColsTerminal;
        if (linesCnt > 1)
            j -= linesCnt-1;
    }

    ASSERT(p != 0);
    ++p;
    return p;
}

/*!\brief Prints the given string with, page by page.
 *
 * \param Buffer     Characters buffer to print.
 * \param BufferLen  Buffer size.
 *
 * \note Doesn't correctly handle \\t and terminal escape sequences when calculating the
 *       number of lines required to print a single line from the Buffer in the terminal.
 *       Maximum length of buffer is limited only by memory size.
 *
 * Note: BufLength should be greater then (KdbNumberOfRowsTerminal * KdbNumberOfColsTerminal).
 *
 */
VOID
KdbpPager(
    IN PCHAR Buffer,
    IN ULONG BufLength)
{
    static CHAR InBuffer[4096];
    static BOOLEAN TerminalInitialized = FALSE;
    static BOOLEAN TerminalConnected = FALSE;
    static BOOLEAN TerminalReportsSize = TRUE;
    CHAR c = '\0';
    PCHAR p, p2;
    ULONG Length;
    ULONG i, j;
    LONG RowsPrintedByTerminal;
    ULONG ScanCode;

    if( BufLength == 0)
      return;

    /* Check if the user has aborted output of the current command */
    if (KdbOutputAborted)
        return;

    /* Initialize the terminal */
    if (!TerminalInitialized)
    {
        KdpDprintf("\x1b[7h");      /* Enable linewrap */

        /* Query terminal type */
        /*DbgPrint("\x1b[Z");*/
        KdpDprintf("\x05");

        TerminalInitialized = TRUE;
        Length = 0;
        KeStallExecutionProcessor(100000);

        for (;;)
        {
            c = KdbpTryGetCharSerial(5000);
            if (c == -1)
                break;

            InBuffer[Length++] = c;
            if (Length >= (sizeof(InBuffer) - 1))
                break;
        }

        InBuffer[Length] = '\0';
        if (Length > 0)
            TerminalConnected = TRUE;
    }

    /* Get number of rows and columns in terminal */
    if ((KdbNumberOfRowsTerminal < 0) || (KdbNumberOfColsTerminal < 0) ||
        (KdbNumberOfRowsPrinted) == 0) /* Refresh terminal size each time when number of rows printed is 0 */
    {
        if ((KdbDebugState & KD_DEBUG_KDSERIAL) && TerminalConnected && TerminalReportsSize)
        {
            /* Try to query number of rows from terminal. A reply looks like "\x1b[8;24;80t" */
            TerminalReportsSize = FALSE;
            KeStallExecutionProcessor(100000);
            KdpDprintf("\x1b[18t");
            c = KdbpTryGetCharSerial(5000);

            if (c == KEY_ESC)
            {
                c = KdbpTryGetCharSerial(5000);
                if (c == '[')
                {
                    Length = 0;

                    for (;;)
                    {
                        c = KdbpTryGetCharSerial(5000);
                        if (c == -1)
                            break;

                        InBuffer[Length++] = c;
                        if (isalpha(c) || Length >= (sizeof(InBuffer) - 1))
                            break;
                    }

                    InBuffer[Length] = '\0';
                    if (InBuffer[0] == '8' && InBuffer[1] == ';')
                    {
                        for (i = 2; (i < Length) && (InBuffer[i] != ';'); i++);

                        if (Buffer[i] == ';')
                        {
                            Buffer[i++] = '\0';

                            /* Number of rows is now at Buffer + 2 and number of cols at Buffer + i */
                            KdbNumberOfRowsTerminal = strtoul(InBuffer + 2, NULL, 0);
                            KdbNumberOfColsTerminal = strtoul(InBuffer + i, NULL, 0);
                            TerminalReportsSize = TRUE;
                        }
                    }
                }
                /* Clear further characters */
                while ((c = KdbpTryGetCharSerial(5000)) != -1);
            }
        }

        if (KdbNumberOfRowsTerminal <= 0)
        {
            /* Set number of rows to the default. */
            KdbNumberOfRowsTerminal = 24;
        }
        else if (KdbNumberOfColsTerminal <= 0)
        {
            /* Set number of cols to the default. */
            KdbNumberOfColsTerminal = 80;
        }
    }

    /* Get the string */
    p = Buffer;

    while (p[0] != '\0')
    {
        if ( p > Buffer+BufLength)
        {
          KdpDprintf("Dmesg: error, p > Buffer+BufLength,d=%d", p - (Buffer+BufLength));
          return;
        }
        i = strcspn(p, "\n");

        // Are we out of buffer?
        if (p + i > Buffer + BufLength)
          // Leaving pager function:
          break;

        /* Calculate the number of lines which will be printed in the terminal
         * when outputting the current line.
         */
        if (i > 0)
            RowsPrintedByTerminal = (i + KdbNumberOfColsPrinted - 1) / KdbNumberOfColsTerminal;
        else
            RowsPrintedByTerminal = 0;

        if (p[i] == '\n')
            RowsPrintedByTerminal++;

        /*DbgPrint("!%d!%d!%d!%d!", KdbNumberOfRowsPrinted, KdbNumberOfColsPrinted, i, RowsPrintedByTerminal);*/

        /* Display a prompt if we printed one screen full of text */
        if (KdbNumberOfRowsTerminal > 0 &&
            (LONG)(KdbNumberOfRowsPrinted + RowsPrintedByTerminal) >= KdbNumberOfRowsTerminal)
        {
            KdbRepeatLastCommand = FALSE;

            if (KdbNumberOfColsPrinted > 0)
                KdpDprintf("\n");

            KdpDprintf("--- Press q to abort, e/End,h/Home,u/PgUp, other key/PgDn ---");
            RowsPrintedByTerminal++;

            if (KdbDebugState & KD_DEBUG_KDSERIAL)
                c = KdbpGetCharSerial();
            else
                c = KdbpGetCharKeyboard(&ScanCode);

            if (c == '\r')
            {
                /* Try to read '\n' which might follow '\r' - if \n is not received here
                 * it will be interpreted as "return" when the next command should be read.
                 */
                if (KdbDebugState & KD_DEBUG_KDSERIAL)
                    c = KdbpTryGetCharSerial(5);
                else
                    c = KdbpTryGetCharKeyboard(&ScanCode, 5);
            }

            //DbgPrint("\n"); //Consize version: don't show pressed key
            KdpDprintf(" '%c'/scan=%04x\n", c, ScanCode); // Shows pressed key

            if (c == 'q')
            {
                KdbOutputAborted = TRUE;
                return;
            }
            if (     ScanCode == KEYSC_END || c=='e')
            {
              PCHAR pBufEnd = Buffer + BufLength;
              p = CountOnePageUp(Buffer, BufLength, pBufEnd);
              i = strcspn(p, "\n");
            }
            else if (ScanCode == KEYSC_PAGEUP  || c=='u')
            {
              p = CountOnePageUp(Buffer, BufLength, p);
              i = strcspn(p, "\n");
            }
            else if (ScanCode == KEYSC_HOME || c=='h')
            {
              p = Buffer;
              i = strcspn(p, "\n");
            }
            else if (ScanCode == KEYSC_ARROWUP)
            {
              p = CountOnePageUp(Buffer, BufLength, p);
              i = strcspn(p, "\n");
            }

            KdbNumberOfRowsPrinted = 0;
            KdbNumberOfColsPrinted = 0;
        }

        /* Insert a NUL after the line and print only the current line. */
        if (p[i] == '\n' && p[i + 1] != '\0')
        {
            c = p[i + 1];
            p[i + 1] = '\0';
        }
        else
        {
            c = '\0';
        }

        /* Remove escape sequences from the line if there's no terminal connected */
        if (!TerminalConnected)
        {
            while ((p2 = strrchr(p, '\x1b'))) /* Look for escape character */
            {
                size_t len = strlen(p2);
                if (p2[1] == '[')
                {
                    j = 2;
                    while (!isalpha(p2[j++]));
                    memmove(p2, p2 + j, len + 1 - j);
                }
                else
                {
                    memmove(p2, p2 + 1, len);
                }
            }
        }

        // The main printing of the current line:
        KdpDprintf(p);

        // restore not null char with saved:
        if (c != '\0')
            p[i + 1] = c;

        /* Set p to the start of the next line and
         * remember the number of rows/cols printed
         */
        p += i;
        if (p[0] == '\n')
        {
            p++;
            KdbNumberOfColsPrinted = 0;
        }
        else
        {
            ASSERT(p[0] == '\0');
            KdbNumberOfColsPrinted += i;
        }

        KdbNumberOfRowsPrinted += RowsPrintedByTerminal;
    }
}

/*!\brief Appends a command to the command history
 *
 * \param Command  Pointer to the command to append to the history.
 */
static VOID
KdbpCommandHistoryAppend(
    IN PCHAR Command)
{
    ULONG Length1 = strlen(Command) + 1;
    ULONG Length2 = 0;
    INT i;
    PCHAR Buffer;

    ASSERT(Length1 <= RTL_NUMBER_OF(KdbCommandHistoryBuffer));

    if (Length1 <= 1 ||
        (KdbCommandHistory[KdbCommandHistoryIndex] &&
         strcmp(KdbCommandHistory[KdbCommandHistoryIndex], Command) == 0))
    {
        return;
    }

    /* Calculate Length1 and Length2 */
    Buffer = KdbCommandHistoryBuffer + KdbCommandHistoryBufferIndex;
    KdbCommandHistoryBufferIndex += Length1;
    if (KdbCommandHistoryBufferIndex >= (LONG)RTL_NUMBER_OF(KdbCommandHistoryBuffer))
    {
        KdbCommandHistoryBufferIndex -= RTL_NUMBER_OF(KdbCommandHistoryBuffer);
        Length2 = KdbCommandHistoryBufferIndex;
        Length1 -= Length2;
    }

    /* Remove previous commands until there is enough space to append the new command */
    for (i = KdbCommandHistoryIndex; KdbCommandHistory[i];)
    {
        if ((Length2 > 0 &&
            (KdbCommandHistory[i] >= Buffer ||
             KdbCommandHistory[i] < (KdbCommandHistoryBuffer + KdbCommandHistoryBufferIndex))) ||
            (Length2 <= 0 &&
             (KdbCommandHistory[i] >= Buffer &&
              KdbCommandHistory[i] < (KdbCommandHistoryBuffer + KdbCommandHistoryBufferIndex))))
        {
            KdbCommandHistory[i] = NULL;
        }

        i--;
        if (i < 0)
            i = RTL_NUMBER_OF(KdbCommandHistory) - 1;

        if (i == KdbCommandHistoryIndex)
            break;
    }

    /* Make sure the new command history entry is free */
    KdbCommandHistoryIndex++;
    KdbCommandHistoryIndex %= RTL_NUMBER_OF(KdbCommandHistory);
    if (KdbCommandHistory[KdbCommandHistoryIndex])
    {
        KdbCommandHistory[KdbCommandHistoryIndex] = NULL;
    }

    /* Append command */
    KdbCommandHistory[KdbCommandHistoryIndex] = Buffer;
    ASSERT((KdbCommandHistory[KdbCommandHistoryIndex] + Length1) <= KdbCommandHistoryBuffer + RTL_NUMBER_OF(KdbCommandHistoryBuffer));
    memcpy(KdbCommandHistory[KdbCommandHistoryIndex], Command, Length1);
    if (Length2 > 0)
    {
        memcpy(KdbCommandHistoryBuffer, Command + Length1, Length2);
    }
}

/*!\brief Reads a line of user-input.
 *
 * \param Buffer  Buffer to store the input into. Trailing newlines are removed.
 * \param Size    Size of \a Buffer.
 *
 * \note Accepts only \n newlines, \r is ignored.
 */
static VOID
KdbpReadCommand(
    OUT PCHAR Buffer,
    IN  ULONG Size)
{
    CHAR Key;
    PCHAR Orig = Buffer;
    ULONG ScanCode = 0;
    BOOLEAN EchoOn;
    static CHAR LastCommand[1024];
    static CHAR NextKey = '\0';
    INT CmdHistIndex = -1;
    INT i;

    EchoOn = !((KdbDebugState & KD_DEBUG_KDNOECHO) != 0);

    for (;;)
    {
        if (KdbDebugState & KD_DEBUG_KDSERIAL)
        {
            Key = (NextKey == '\0') ? KdbpGetCharSerial() : NextKey;
            NextKey = '\0';
            ScanCode = 0;
            if (Key == KEY_ESC) /* ESC */
            {
                Key = KdbpGetCharSerial();
                if (Key == '[')
                {
                    Key = KdbpGetCharSerial();

                    switch (Key)
                    {
                        case 'A':
                            ScanCode = KEY_SCAN_UP;
                            break;
                        case 'B':
                            ScanCode = KEY_SCAN_DOWN;
                            break;
                        case 'C':
                            break;
                        case 'D':
                            break;
                    }
                }
            }
        }
        else
        {
            ScanCode = 0;
            Key = (NextKey == '\0') ? KdbpGetCharKeyboard(&ScanCode) : NextKey;
            NextKey = '\0';
        }

        if ((ULONG)(Buffer - Orig) >= (Size - 1))
        {
            /* Buffer is full, accept only newlines */
            if (Key != '\n')
                continue;
        }

        if (Key == '\r')
        {
            /* Read the next char - this is to throw away a \n which most clients should
             * send after \r.
             */
            KeStallExecutionProcessor(100000);

            if (KdbDebugState & KD_DEBUG_KDSERIAL)
                NextKey = KdbpTryGetCharSerial(5);
            else
                NextKey = KdbpTryGetCharKeyboard(&ScanCode, 5);

            if (NextKey == '\n' || NextKey == -1) /* \n or no response at all */
                NextKey = '\0';

            KdbpPrint("\n");

            /*
             * Repeat the last command if the user presses enter. Reduces the
             * risk of RSI when single-stepping.
             */
            if (Buffer != Orig)
            {
                KdbRepeatLastCommand = TRUE;
                *Buffer = '\0';
                RtlStringCbCopyA(LastCommand, sizeof(LastCommand), Orig);
            }
            else if (KdbRepeatLastCommand)
                RtlStringCbCopyA(Buffer, Size, LastCommand);
            else
                *Buffer = '\0';

            return;
        }
        else if (Key == KEY_BS || Key == KEY_DEL)
        {
            if (Buffer > Orig)
            {
                Buffer--;
                *Buffer = 0;

                if (EchoOn)
                    KdbpPrint("%c %c", KEY_BS, KEY_BS);
                else
                    KdbpPrint(" %c", KEY_BS);
            }
        }
        else if (ScanCode == KEY_SCAN_UP)
        {
            BOOLEAN Print = TRUE;

            if (CmdHistIndex < 0)
            {
                CmdHistIndex = KdbCommandHistoryIndex;
            }
            else
            {
                i = CmdHistIndex - 1;

                if (i < 0)
                    CmdHistIndex = RTL_NUMBER_OF(KdbCommandHistory) - 1;

                if (KdbCommandHistory[i] && i != KdbCommandHistoryIndex)
                    CmdHistIndex = i;
                else
                    Print = FALSE;
            }

            if (Print && KdbCommandHistory[CmdHistIndex])
            {
                while (Buffer > Orig)
                {
                    Buffer--;
                    *Buffer = 0;

                    if (EchoOn)
                        KdbpPrint("%c %c", KEY_BS, KEY_BS);
                    else
                        KdbpPrint(" %c", KEY_BS);
                }

                i = min(strlen(KdbCommandHistory[CmdHistIndex]), Size - 1);
                memcpy(Orig, KdbCommandHistory[CmdHistIndex], i);
                Orig[i] = '\0';
                Buffer = Orig + i;
                KdbpPrint("%s", Orig);
            }
        }
        else if (ScanCode == KEY_SCAN_DOWN)
        {
            if (CmdHistIndex > 0 && CmdHistIndex != KdbCommandHistoryIndex)
            {
                i = CmdHistIndex + 1;
                if (i >= (INT)RTL_NUMBER_OF(KdbCommandHistory))
                    i = 0;

                if (KdbCommandHistory[i])
                {
                    CmdHistIndex = i;
                    while (Buffer > Orig)
                    {
                        Buffer--;
                        *Buffer = 0;

                        if (EchoOn)
                            KdbpPrint("%c %c", KEY_BS, KEY_BS);
                        else
                            KdbpPrint(" %c", KEY_BS);
                    }

                    i = min(strlen(KdbCommandHistory[CmdHistIndex]), Size - 1);
                    memcpy(Orig, KdbCommandHistory[CmdHistIndex], i);
                    Orig[i] = '\0';
                    Buffer = Orig + i;
                    KdbpPrint("%s", Orig);
                }
            }
        }
        else
        {
            if (EchoOn)
                KdbpPrint("%c", Key);

            *Buffer = Key;
            Buffer++;
        }
    }
}


BOOLEAN
NTAPI
KdbRegisterCliCallback(
    PVOID Callback,
    BOOLEAN Deregister)
{
    ULONG i;

    /* Loop all entries */
    for (i = 0; i < _countof(KdbCliCallbacks); i++)
    {
        /* Check if deregistering was requested */
        if (Deregister)
        {
            /* Check if this entry is the one that was registered */
            if (KdbCliCallbacks[i] == Callback)
            {
                /* Delete it and report success */
                KdbCliCallbacks[i] = NULL;
                return TRUE;
            }
        }
        else
        {
            /* Check if this entry is free */
            if (KdbCliCallbacks[i] == NULL)
            {
                /* Set it and and report success */
                KdbCliCallbacks[i] = Callback;
                return TRUE;
            }
        }
    }

    /* Unsuccessful */
    return FALSE;
}

/*! \brief Invokes registered CLI callbacks until one of them handled the
 *         Command.
 *
 * \param Command - Command line to parse and execute if possible.
 * \param Argc - Number of arguments in Argv
 * \param Argv - Array of strings, each of them containing one argument.
 *
 * \return TRUE, if the command was handled, FALSE if it was not handled.
 */
static
BOOLEAN
KdbpInvokeCliCallbacks(
    IN PCHAR Command,
    IN ULONG Argc,
    IN PCHAR Argv[])
{
    ULONG i;

    /* Loop all entries */
    for (i = 0; i < _countof(KdbCliCallbacks); i++)
    {
        /* Check if this entry is registered */
        if (KdbCliCallbacks[i])
        {
            /* Invoke the callback and check if it handled the command */
            if (KdbCliCallbacks[i](Command, Argc, Argv))
            {
                return TRUE;
            }
        }
    }

    /* None of the callbacks handled the command */
    return FALSE;
}


/*!\brief Parses command line and executes command if found
 *
 * \param Command    Command line to parse and execute if possible.
 *
 * \retval TRUE   Don't continue execution.
 * \retval FALSE  Continue execution (leave KDB)
 */
static BOOLEAN
KdbpDoCommand(
    IN PCHAR Command)
{
    ULONG i;
    PCHAR p;
    ULONG Argc;
    // FIXME: for what do we need a 1024 characters command line and 256 tokens?
    static PCHAR Argv[256];
    static CHAR OrigCommand[1024];

    RtlStringCbCopyA(OrigCommand, sizeof(OrigCommand), Command);

    Argc = 0;
    p = Command;

    for (;;)
    {
        while (*p == '\t' || *p == ' ')
            p++;

        if (*p == '\0')
            break;

        i = strcspn(p, "\t ");
        Argv[Argc++] = p;
        p += i;
        if (*p == '\0')
            break;

        *p = '\0';
        p++;
    }

    if (Argc < 1)
        return TRUE;

    for (i = 0; i < RTL_NUMBER_OF(KdbDebuggerCommands); i++)
    {
        if (!KdbDebuggerCommands[i].Name)
            continue;

        if (strcmp(KdbDebuggerCommands[i].Name, Argv[0]) == 0)
        {
            return KdbDebuggerCommands[i].Fn(Argc, Argv);
        }
    }

    /* Now invoke the registered callbacks */
    if (KdbpInvokeCliCallbacks(Command, Argc, Argv))
    {
        return TRUE;
    }

    KdbpPrint("Command '%s' is unknown.\n", OrigCommand);
    return TRUE;
}

/*!\brief KDB Main Loop.
 *
 * \param EnteredOnSingleStep  TRUE if KDB was entered on single step.
 */
VOID
KdbpCliMainLoop(
    IN BOOLEAN EnteredOnSingleStep)
{
    static CHAR Command[1024];
    BOOLEAN Continue;

    if (EnteredOnSingleStep)
    {
        if (!KdbSymPrintAddress((PVOID)KeGetContextPc(KdbCurrentTrapFrame), KdbCurrentTrapFrame))
        {
            KdbpPrint("<%p>", KeGetContextPc(KdbCurrentTrapFrame));
        }

        KdbpPrint(": ");
        if (KdbpDisassemble(KeGetContextPc(KdbCurrentTrapFrame), KdbUseIntelSyntax) < 0)
        {
            KdbpPrint("<INVALID>");
        }
        KdbpPrint("\n");
    }

    /* Flush the input buffer */
    if (KdbDebugState & KD_DEBUG_KDSERIAL)
    {
        while (KdbpTryGetCharSerial(1) != -1);
    }
    else
    {
        ULONG ScanCode;
        while (KdbpTryGetCharKeyboard(&ScanCode, 1) != -1);
    }

    /* Main loop */
    do
    {
        /* Reset the number of rows/cols printed */
        KdbNumberOfRowsPrinted = KdbNumberOfColsPrinted = 0;

        /* Print the prompt */
        KdbpPrint(KdbPromptString.Buffer);

        /* Read a command and remember it */
        KdbpReadCommand(Command, sizeof(Command));
        KdbpCommandHistoryAppend(Command);

        /* Reset the number of rows/cols printed and output aborted state */
        KdbNumberOfRowsPrinted = KdbNumberOfColsPrinted = 0;
        KdbOutputAborted = FALSE;

        /* Call the command */
        Continue = KdbpDoCommand(Command);
        KdbOutputAborted = FALSE;
    }
    while (Continue);
}

/*!\brief Called when a module is loaded.
 *
 * \param Name  Filename of the module which was loaded.
 */
VOID
KdbpCliModuleLoaded(
    IN PUNICODE_STRING Name)
{
    if (!KdbBreakOnModuleLoad)
        return;

    KdbpPrint("Module %wZ loaded.\n", Name);
    DbgBreakPointWithStatus(DBG_STATUS_CONTROL_C);
}

/*!\brief This function is called by KdbEnterDebuggerException...
 *
 * Used to interpret the init file in a context with a trapframe setup
 * (KdbpCliInit call KdbEnter which will call KdbEnterDebuggerException which will
 * call this function if KdbInitFileBuffer is not NULL.
 */
VOID
KdbpCliInterpretInitFile(VOID)
{
    PCHAR p1, p2;
    INT i;
    CHAR c;

    /* Execute the commands in the init file */
    DPRINT("KDB: Executing KDBinit file...\n");
    p1 = KdbInitFileBuffer;
    while (p1[0] != '\0')
    {
        i = strcspn(p1, "\r\n");
        if (i > 0)
        {
            c = p1[i];
            p1[i] = '\0';

            /* Look for "break" command and comments */
            p2 = p1;

            while (isspace(p2[0]))
                p2++;

            if (strncmp(p2, "break", sizeof("break")-1) == 0 &&
                (p2[sizeof("break")-1] == '\0' || isspace(p2[sizeof("break")-1])))
            {
                /* break into the debugger */
                KdbpCliMainLoop(FALSE);
            }
            else if (p2[0] != '#' && p2[0] != '\0') /* Ignore empty lines and comments */
            {
                KdbpDoCommand(p1);
            }

            p1[i] = c;
        }

        p1 += i;
        while (p1[0] == '\r' || p1[0] == '\n')
            p1++;
    }
    DPRINT("KDB: KDBinit executed\n");
}

/*!\brief Called when KDB is initialized
 *
 * Reads the KDBinit file from the SystemRoot\System32\drivers\etc directory and executes it.
 */
VOID
KdbpCliInit(VOID)
{
    NTSTATUS Status;
    OBJECT_ATTRIBUTES ObjectAttributes;
    UNICODE_STRING FileName;
    IO_STATUS_BLOCK Iosb;
    FILE_STANDARD_INFORMATION FileStdInfo;
    HANDLE hFile = NULL;
    INT FileSize;
    PCHAR FileBuffer;
    ULONG OldEflags;

    /* Initialize the object attributes */
    RtlInitUnicodeString(&FileName, L"\\SystemRoot\\System32\\drivers\\etc\\KDBinit");
    InitializeObjectAttributes(&ObjectAttributes,
                               &FileName,
                               OBJ_CASE_INSENSITIVE | OBJ_KERNEL_HANDLE,
                               NULL,
                               NULL);

    /* Open the file */
    Status = ZwOpenFile(&hFile, FILE_READ_DATA | SYNCHRONIZE,
                        &ObjectAttributes, &Iosb, 0,
                        FILE_NON_DIRECTORY_FILE | FILE_SYNCHRONOUS_IO_NONALERT |
                        FILE_NO_INTERMEDIATE_BUFFERING);
    if (!NT_SUCCESS(Status))
    {
        DPRINT("Could not open \\SystemRoot\\System32\\drivers\\etc\\KDBinit (Status 0x%x)", Status);
        return;
    }

    /* Get the size of the file */
    Status = ZwQueryInformationFile(hFile, &Iosb, &FileStdInfo, sizeof(FileStdInfo),
                                    FileStandardInformation);
    if (!NT_SUCCESS(Status))
    {
        ZwClose(hFile);
        DPRINT("Could not query size of \\SystemRoot\\System32\\drivers\\etc\\KDBinit (Status 0x%x)", Status);
        return;
    }
    FileSize = FileStdInfo.EndOfFile.u.LowPart;

    /* Allocate memory for the file */
    FileBuffer = ExAllocatePool(PagedPool, FileSize + 1); /* add 1 byte for terminating '\0' */
    if (!FileBuffer)
    {
        ZwClose(hFile);
        DPRINT("Could not allocate %d bytes for KDBinit file\n", FileSize);
        return;
    }

    /* Load file into memory */
    Status = ZwReadFile(hFile, NULL, NULL, NULL, &Iosb, FileBuffer, FileSize, NULL, NULL);
    ZwClose(hFile);

    if (!NT_SUCCESS(Status) && Status != STATUS_END_OF_FILE)
    {
        ExFreePool(FileBuffer);
        DPRINT("Could not read KDBinit file into memory (Status 0x%lx)\n", Status);
        return;
    }

    FileSize = min(FileSize, (INT)Iosb.Information);
    FileBuffer[FileSize] = '\0';

    /* Enter critical section */
    OldEflags = __readeflags();
    _disable();

    /* Interpret the init file... */
    KdbInitFileBuffer = FileBuffer;
    //KdbEnter(); // FIXME
    KdbInitFileBuffer = NULL;

    /* Leave critical section */
    __writeeflags(OldEflags);

    ExFreePool(FileBuffer);
}