/* $Id: DevVirtualKD.cpp 82149 2019-11-24 16:25:49Z vboxsync $ */
/** @file
 * VirtualKD - Device stub/loader for fast Windows kernel-mode debugging.
 *
 * Contributed by: Ivan Shcherbakov
 * Heavily modified after the contribution.
 */

/*
 * Copyright (C) 2010-2019 Oracle Corporation
 *
 * This file is part of VirtualBox Open Source Edition (OSE), as
 * available from http://www.virtualbox.org. This file is free software;
 * you can redistribute it and/or modify it under the terms of the GNU
 * General Public License (GPL) as published by the Free Software
 * Foundation, in version 2 as it comes in the "COPYING" file of the
 * VirtualBox OSE distribution. VirtualBox OSE is distributed in the
 * hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
 */


/*********************************************************************************************************************************
*   Header Files                                                                                                                 *
*********************************************************************************************************************************/
#define LOG_GROUP LOG_GROUP_DEV // LOG_GROUP_DEV_VIRTUALKD
#include <VBox/vmm/pdmdev.h>
#include <VBox/log.h>
#include <iprt/assert.h>
#include <iprt/path.h>

#include "VBoxDD.h"


/*********************************************************************************************************************************
*   Defined Constants And Macros                                                                                                 *
*********************************************************************************************************************************/
#define IKDClient_InterfaceVersion 3


/*********************************************************************************************************************************
*   Structures and Typedefs                                                                                                      *
*********************************************************************************************************************************/
typedef struct VKDREQUESTHDR
{
    unsigned cbData;
    unsigned cbReplyMax;
} VKDREQUESTHDR;

#pragma pack(1)
typedef struct VKDREPLYHDR
{
    unsigned cbData;
    char chOne;
    char chSpace;
} VKDREPLYHDR;
#pragma pack()
AssertCompileSize(VKDREPLYHDR, 6);

class IKDClient
{
public:
    virtual unsigned OnRequest(const char *pRequestIncludingRpcHeader, unsigned RequestSizeWithRpcHeader, char **ppReply)=0;
    virtual ~IKDClient() {}
};

typedef IKDClient *(*PFNCreateVBoxKDClientEx)(unsigned version);

typedef struct VIRTUALKD
{
    bool fOpenChannelDetected;
    bool fChannelDetectSuccessful;
    RTLDRMOD hLib;
    IKDClient *pKDClient;
    char abCmdBody[_256K];
} VIRTUALKD;




static DECLCALLBACK(VBOXSTRICTRC) vkdPortRead(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT offPort, uint32_t *pu32, unsigned cb)
{
    RT_NOREF(pvUser, offPort, cb);
    VIRTUALKD *pThis = PDMDEVINS_2_DATA(pDevIns, VIRTUALKD *);

    if (pThis->fOpenChannelDetected)
    {
        *pu32 = RT_MAKE_U32_FROM_U8('V', 'B', 'O', 'X');    /* 'XOBV', checked in VMWRPC.H */
        pThis->fOpenChannelDetected = false;
        pThis->fChannelDetectSuccessful = true;
    }
    else
        *pu32 = UINT32_MAX;

    return VINF_SUCCESS;
}

static DECLCALLBACK(VBOXSTRICTRC) vkdPortWrite(PPDMDEVINS pDevIns, void *pvUser, RTIOPORT offPort, uint32_t u32, unsigned cb)
{
    RT_NOREF(pvUser, cb);
    VIRTUALKD *pThis = PDMDEVINS_2_DATA(pDevIns, VIRTUALKD *);

    if (offPort == 1)
    {
        RTGCPHYS GCPhys = u32;
        VKDREQUESTHDR RequestHeader = {0, };
        int rc = PDMDevHlpPhysRead(pDevIns, GCPhys, &RequestHeader, sizeof(RequestHeader));
        if (   !RT_SUCCESS(rc)
            || !RequestHeader.cbData)
            return VINF_SUCCESS;

        unsigned cbData = RT_MIN(RequestHeader.cbData, sizeof(pThis->abCmdBody));
        rc = PDMDevHlpPhysRead(pDevIns, GCPhys + sizeof(RequestHeader), pThis->abCmdBody, cbData);
        if (!RT_SUCCESS(rc))
            return VINF_SUCCESS;

        char *pReply = NULL;
        unsigned cbReply = pThis->pKDClient->OnRequest(pThis->abCmdBody, cbData, &pReply);

        if (!pReply)
            cbReply = 0;

        /** @todo r=bird: RequestHeader.cbReplyMax is not taking into account here. */
        VKDREPLYHDR ReplyHeader;
        ReplyHeader.cbData = cbReply + 2;
        ReplyHeader.chOne = '1';
        ReplyHeader.chSpace = ' ';
        rc = PDMDevHlpPhysWrite(pDevIns, GCPhys, &ReplyHeader, sizeof(ReplyHeader));
        if (!RT_SUCCESS(rc))
            return VINF_SUCCESS;
        if (cbReply)
        {
            rc = PDMDevHlpPhysWrite(pDevIns, GCPhys + sizeof(ReplyHeader), pReply, cbReply);
            if (!RT_SUCCESS(rc))
                return VINF_SUCCESS;
        }
    }
    else
    {
        Assert(offPort == 0);
        if (u32 == 0x564D5868)
            pThis->fOpenChannelDetected = true;
        else
            pThis->fOpenChannelDetected = false;
    }

    return VINF_SUCCESS;
}


/**
 * @interface_method_impl{PDMDEVREG,pfnDestruct}
 */
static DECLCALLBACK(int) vkdDestruct(PPDMDEVINS pDevIns)
{
    PDMDEV_CHECK_VERSIONS_RETURN(pDevIns);
    VIRTUALKD *pThis = PDMDEVINS_2_DATA(pDevIns, VIRTUALKD *);

    if (pThis->pKDClient)
    {
        delete pThis->pKDClient;
        pThis->pKDClient = NULL;
    }

    if (pThis->hLib != NIL_RTLDRMOD)
    {
        RTLdrClose(pThis->hLib);
        pThis->hLib = NIL_RTLDRMOD;
    }

    return VINF_SUCCESS;
}


/**
 * @interface_method_impl{PDMDEVREG,pfnConstruct}
 */
static DECLCALLBACK(int) vkdConstruct(PPDMDEVINS pDevIns, int iInstance, PCFGMNODE pCfg)
{
    PDMDEV_CHECK_VERSIONS_RETURN(pDevIns);
    VIRTUALKD *pThis = PDMDEVINS_2_DATA(pDevIns, VIRTUALKD *);
    RT_NOREF(iInstance);

    pThis->fOpenChannelDetected = false;
    pThis->fChannelDetectSuccessful = false;
    pThis->hLib = NIL_RTLDRMOD;
    pThis->pKDClient = NULL;


    PDMDEV_VALIDATE_CONFIG_RETURN(pDevIns, "Path", "");

    /* This device is a bit unusual, after this point it will not fail to be
     * constructed, but there will be a warning and it will not work. */

    char szPath[RTPATH_MAX];
    int rc = CFGMR3QueryStringDef(pCfg, "Path", szPath, sizeof(szPath) - sizeof("kdclient64.dll"), "");
    if (RT_FAILURE(rc))
        return PDMDEV_SET_ERROR(pDevIns, rc, N_("Configuration error: Failed to get the \"Path\" value"));

    rc = RTPathAppend(szPath, sizeof(szPath), HC_ARCH_BITS == 64 ?  "kdclient64.dll" : "kdclient.dll");
    AssertRCReturn(rc, rc);
    rc = RTLdrLoad(szPath, &pThis->hLib);
    if (RT_SUCCESS(rc))
    {
        PFNCreateVBoxKDClientEx pfnInit;
        rc = RTLdrGetSymbol(pThis->hLib, "CreateVBoxKDClientEx", (void **)&pfnInit);
        if (RT_SUCCESS(rc))
        {
            pThis->pKDClient = pfnInit(IKDClient_InterfaceVersion);
            if (pThis->pKDClient)
            {
                IOMIOPORTHANDLE hIoPorts;
                rc = PDMDevHlpIoPortCreateAndMap(pDevIns, 0x5658 /*uPort*/, 2 /*cPorts*/, vkdPortWrite, vkdPortRead,
                                                 "VirtualKD",  NULL /*paExtDescs*/, &hIoPorts);
                AssertRCReturn(rc, rc);
            }
            else
                PDMDevHlpVMSetRuntimeError(pDevIns, 0 /* fFlags */, "VirtualKD_INIT",
                                           N_("Failed to initialize VirtualKD library '%s'. Fast kernel-mode debugging will not work"), szPath);
        }
        else
            PDMDevHlpVMSetRuntimeError(pDevIns, 0 /* fFlags */, "VirtualKD_SYMBOL",
                                       N_("Failed to find entry point for VirtualKD library '%s'. Fast kernel-mode debugging will not work"), szPath);
    }
    else
        PDMDevHlpVMSetRuntimeError(pDevIns, 0 /* fFlags */, "VirtualKD_LOAD",
                                   N_("Failed to load VirtualKD library '%s'. Fast kernel-mode debugging will not work"), szPath);
    return VINF_SUCCESS;
}


/**
 * The device registration structure.
 */
const PDMDEVREG g_DeviceVirtualKD =
{
    /* .u32Version = */             PDM_DEVREG_VERSION,
    /* .uReserved0 = */             0,
    /* .szName = */                 "VirtualKD",
    /* .fFlags = */                 PDM_DEVREG_FLAGS_DEFAULT_BITS | PDM_DEVREG_FLAGS_NEW_STYLE,
    /* .fClass = */                 PDM_DEVREG_CLASS_MISC,
    /* .cMaxInstances = */          1,
    /* .uSharedVersion = */         42,
    /* .cbInstanceShared = */       sizeof(VIRTUALKD),
    /* .cbInstanceCC = */           0,
    /* .cbInstanceRC = */           0,
    /* .cMaxPciDevices = */         0,
    /* .cMaxMsixVectors = */        0,
    /* .pszDescription = */         "Provides fast debugging interface when debugging Windows kernel",
#if defined(IN_RING3)
    /* .pszRCMod = */               "",
    /* .pszR0Mod = */               "",
    /* .pfnConstruct = */           vkdConstruct,
    /* .pfnDestruct = */            vkdDestruct,
    /* .pfnRelocate = */            NULL,
    /* pfnIOCtl */    NULL,
    /* .pfnPowerOn = */             NULL,
    /* .pfnReset = */               NULL,
    /* .pfnSuspend = */             NULL,
    /* .pfnResume = */              NULL,
    /* .pfnAttach = */              NULL,
    /* .pfnDetach = */              NULL,
    /* .pfnQueryInterface = */      NULL,
    /* .pfnInitComplete = */        NULL,
    /* .pfnPowerOff = */            NULL,
    /* .pfnSoftReset = */           NULL,
    /* .pfnReserved0 = */           NULL,
    /* .pfnReserved1 = */           NULL,
    /* .pfnReserved2 = */           NULL,
    /* .pfnReserved3 = */           NULL,
    /* .pfnReserved4 = */           NULL,
    /* .pfnReserved5 = */           NULL,
    /* .pfnReserved6 = */           NULL,
    /* .pfnReserved7 = */           NULL,
#elif defined(IN_RING0)
    /* .pfnEarlyConstruct = */      NULL,
    /* .pfnConstruct = */           NULL,
    /* .pfnDestruct = */            NULL,
    /* .pfnFinalDestruct = */       NULL,
    /* .pfnRequest = */             NULL,
    /* .pfnReserved0 = */           NULL,
    /* .pfnReserved1 = */           NULL,
    /* .pfnReserved2 = */           NULL,
    /* .pfnReserved3 = */           NULL,
    /* .pfnReserved4 = */           NULL,
    /* .pfnReserved5 = */           NULL,
    /* .pfnReserved6 = */           NULL,
    /* .pfnReserved7 = */           NULL,
#elif defined(IN_RC)
    /* .pfnConstruct = */           NULL,
    /* .pfnReserved0 = */           NULL,
    /* .pfnReserved1 = */           NULL,
    /* .pfnReserved2 = */           NULL,
    /* .pfnReserved3 = */           NULL,
    /* .pfnReserved4 = */           NULL,
    /* .pfnReserved5 = */           NULL,
    /* .pfnReserved6 = */           NULL,
    /* .pfnReserved7 = */           NULL,
#else
# error "Not in IN_RING3, IN_RING0 or IN_RC!"
#endif
    /* .u32VersionEnd = */          PDM_DEVREG_VERSION
};