/****************************** Module Header ******************************\
* Module Name: srvhook.c
*
* Copyright (c) 1985 - 1999, Microsoft Corporation
*
* Server side of hook calls and callbacks.
*
* 05-09-91 ScottLu      Created.
\***************************************************************************/

#include "precomp.h"
#pragma hdrstop

LRESULT fnHkINLPCBTCREATESTRUCT(UINT msg, WPARAM wParam, LPCBT_CREATEWND pcbt,
    PROC xpfnProc, BOOL bAnsi);

/***************************************************************************\
* xxxHkCallHook
*
* This is the server-side stub that calls to the client to call the actual
* hook function.
*
* History:
* 05-09-91 ScottLu      Rewrote to make all hooks work client/server!
* 01-28-91 DavidPe      Created.
\***************************************************************************/

LRESULT xxxHkCallHook(
    PHOOK phk,
    int nCode,
    WPARAM wParam,
    LPARAM lParam)
{
    LRESULT nRet;
    PROC pfnHk, pfnHookProc;
    PPFNCLIENT ppfnClient;
    PCWPSTRUCTEX pcwp;
    PCWPRETSTRUCTEX pcwpret;
    PCLIENTINFO pci;
    ULONG_PTR dwHookData;
    ULONG_PTR dwFlags;
    struct tagSMS *psms;
#ifdef LATER
    /*
     * WindowsBug 246329
     * The code was supposed to prevent the backdoor
     * for the surprise foreground change.
     * However, the implementation below locks the
     * entire system, preventing the legit, expected
     * foreground change too. It's obvious on MP systems.
     * E.g. in the case global hooks such as
     * GETMESSAGEHOOK are installed, the chances are
     * pretty high.
     * For this time being, instead of making the lock
     * per process or per thread, we decided to simply
     * disable the foreground lock during the hook
     * callback.
     */
    TL tlSFWLock;
    BOOL fLockForeground;
#endif

    DbgValidateHooks(phk, phk->iHook);
    /*
     * Only low level hooks are allowed in the RIT context.
     * Also asssert that the hook is not destroyed
     */
#ifdef REDIRECTION
    UserAssert((PtiCurrent() != gptiRit)
               || (phk->iHook == WH_MOUSE_LL)
               || (phk->iHook == WH_KEYBOARD_LL)
               || (phk->iHook == WH_HITTEST));
#else
    UserAssert((PtiCurrent() != gptiRit)
               || (phk->iHook == WH_MOUSE_LL)
               || (phk->iHook == WH_KEYBOARD_LL));
#endif // REDIRECTION

    /*
     * While we're still inside the critical section make sure the
     * hook hasn't been 'freed'.  If so just return 0.
     */
    if (phk->offPfn != 0) {
        pfnHookProc = PFNHOOK(phk);
    } else {
        return 0;
    }

    ppfnClient = (phk->flags & HF_ANSI) ? &gpsi->apfnClientA :
            &gpsi->apfnClientW;

#ifdef LATER    // per 246329
    /*
     * LATER5.0 GerardoB. This might generate some hate reactions but I'm
     *  not sure we want people hooking just to steal the foreground.
     * Prevent hookprocs from other processes from switching the foreground
     */
    fLockForeground = (GETPTI(phk)->ppi != PpiCurrent());
    if (fLockForeground) {
        ThreadLockSFWLockCount(&tlSFWLock);
    }
#endif

    switch(phk->iHook) {
    case WH_CALLWNDPROC:
    case WH_CALLWNDPROCRET:
       if (phk->iHook == WH_CALLWNDPROC) {
          pcwp = (PCWPSTRUCTEX)lParam;
          psms = pcwp->psmsSender;
       } else {
          pcwpret = (PCWPRETSTRUCTEX)lParam;
          psms = pcwpret->psmsSender;
       }

        /*
         * If the sender has died or timed out, don't call the
         * hook because any memory the message points to may be invalid.
         */
        if (psms != NULL && (psms->flags & (SMF_SENDERDIED | SMF_REPLY))) {
            nRet = 0;
            break;
        }

        /*
         * This is the hardest of the hooks because we need to thunk through
         * the message hooks in order to deal with synchronously sent messages
         * that point to structures - to get the structures passed across
         * alright, etc.
         *
         * This will call a special client-side routine that'll rebundle the
         * arguments and call the hook in the right format.
         *
         * Currently, the message thunk callbacks to the client-side don't take
         * enough parameters to pass wParam (which == fInterThread send msg).
         * To do this, call one of two functions.
         */
        pci = GetClientInfo();
        if (phk->iHook == WH_CALLWNDPROC) {
            pfnHk = ppfnClient->pfnHkINLPCWPSTRUCT;
        } else {
            pfnHk = ppfnClient->pfnHkINLPCWPRETSTRUCT;
            try {
                pci->dwHookData = pcwpret->lResult;
            } except (W32ExceptionHandler(FALSE, RIP_WARNING)) {
                nRet = 0;
                break;
            }
        }

        /*
         * Save current hook state.
         */
        try {
            dwFlags = pci->CI_flags & CI_INTERTHREAD_HOOK;
            dwHookData = pci->dwHookData;

            if (wParam) {
                pci->CI_flags |= CI_INTERTHREAD_HOOK;
            } else {
                pci->CI_flags &= ~CI_INTERTHREAD_HOOK;
            }
        } except (W32ExceptionHandler(FALSE, RIP_WARNING)) {
            nRet = 0;
            break;
        }
        if (phk->iHook == WH_CALLWNDPROC) {
           nRet = ScSendMessageSMS(
               PW(pcwp->hwnd),
               pcwp->message,
               pcwp->wParam,
               pcwp->lParam,
               (ULONG_PTR)pfnHookProc, pfnHk,
               (phk->flags & HF_ANSI) ?
                       (SCMS_FLAGS_ANSI|SCMS_FLAGS_INONLY) :
                       SCMS_FLAGS_INONLY,
               psms);
        } else {
            nRet = ScSendMessageSMS(
                PW(pcwpret->hwnd),
                pcwpret->message,
                pcwpret->wParam,
                pcwpret->lParam,
                (ULONG_PTR)pfnHookProc, pfnHk,
                (phk->flags & HF_ANSI) ?
                        (SCMS_FLAGS_ANSI|SCMS_FLAGS_INONLY) :
                        SCMS_FLAGS_INONLY,
                psms);
        }
        /*
         * Restore previous hook state.
         */
        try {
            pci->CI_flags ^= ((pci->CI_flags ^ dwFlags) & CI_INTERTHREAD_HOOK);
            pci->dwHookData = dwHookData;
        } except (W32ExceptionHandler(FALSE, RIP_WARNING)) {
            nRet = 0;
        }
        break;
    case WH_CBT:
        /*
         * There are many different types of CBT hooks!
         */
        switch(nCode) {
        case HCBT_CLICKSKIPPED:
            goto MouseHook;
            break;

        case HCBT_CREATEWND:
            /*
             * This hook type points to a CREATESTRUCT, so we need to
             * be fancy with it's thunking, because a CREATESTRUCT contains
             * a pointer to CREATEPARAMS which can be anything...  so
             * funnel this through our message thunks.
             */
            nRet = fnHkINLPCBTCREATESTRUCT(
                    MAKELONG((WORD)nCode, (WORD)phk->iHook),
                    wParam,
                    (LPCBT_CREATEWND)lParam,
                    pfnHookProc,
                    (phk->flags & HF_ANSI) ? TRUE : FALSE);
            break;

#ifdef REDIRECTION
        case HCBT_GETCURSORPOS:

            /*
             * This hook type points to a POINT structure, so it's pretty
             * simple.
             */
            nRet = fnHkINLPPOINT(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                    wParam, (LPPOINT)lParam, (ULONG_PTR)pfnHookProc,
                    ppfnClient->pfnDispatchHook);
            break;
#endif // REDIRECTION

        case HCBT_MOVESIZE:

            /*
             * This hook type points to a RECT structure, so it's pretty
             * simple.
             */
            nRet = fnHkINLPRECT(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                    wParam, (LPRECT)lParam, (ULONG_PTR)pfnHookProc,
                    ppfnClient->pfnDispatchHook);
            break;

        case HCBT_ACTIVATE:
            /*
             * This hook type points to a CBTACTIVATESTRUCT
             */
            nRet = fnHkINLPCBTACTIVATESTRUCT(MAKELONG((UINT)nCode,
                    (UINT)phk->iHook), wParam, (LPCBTACTIVATESTRUCT)lParam,
                    (ULONG_PTR)pfnHookProc, ppfnClient->pfnDispatchHook);
            break;

        default:

            /*
             * The rest of the cbt hooks are all dword parameters.
             */
            nRet = fnHkINDWORD(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                    wParam, lParam, (ULONG_PTR)pfnHookProc,
                    ppfnClient->pfnDispatchHook, &phk->flags);
            break;
        }
        break;

    case WH_FOREGROUNDIDLE:
        /*
         * These are dword parameters and are therefore real easy.
         *
         */
        nRet = fnHkINDWORD(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, lParam, (ULONG_PTR)pfnHookProc,
                ppfnClient->pfnDispatchHook, &phk->flags);
        break;

    case WH_SHELL:

        if (nCode == HSHELL_GETMINRECT) {
            /*
             * This hook type points to a RECT structure, so it's pretty
             * simple.
             */
            nRet = fnHkINLPRECT(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                    wParam, (LPRECT)lParam, (ULONG_PTR)pfnHookProc,
                    ppfnClient->pfnDispatchHook);
            break;
        }

        /*
         * Otherwise fall through to the simple case of DWORD below
         */

    case WH_KEYBOARD:
        /*
         * These are dword parameters and are therefore real easy.
         */
        nRet = fnHkINDWORD(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, lParam, (ULONG_PTR)pfnHookProc,
                ppfnClient->pfnDispatchHook, &phk->flags);
        break;

    case WH_MSGFILTER:
    case WH_SYSMSGFILTER:
    case WH_GETMESSAGE:
        /*
         * These take an lpMsg as their last parameter.  Since these are
         * exclusively posted parameters, and since nowhere on the server
         * do we post a message with a pointer to some other structure in
         * it, the lpMsg structure contents can all be treated verbatim.
         */
        nRet = fnHkINLPMSG(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, (LPMSG)lParam, (ULONG_PTR)pfnHookProc,
                ppfnClient->pfnDispatchHook,
                (phk->flags & HF_ANSI) ? TRUE : FALSE, &phk->flags);
        break;

    case WH_JOURNALPLAYBACK:

#ifdef HOOKBATCH
        /*
         * If this hook has cached playback info then we need to grab
         * the info out of the cache.
         */

        if (phk->cEventMessages) {
            if (nCode == HC_GETNEXT) {
                LPEVENTMSG pEventMsg;
                pEventMsg = (LPEVENTMSG)lParam;

                if (phk->flags & HF_NEEDHC_SKIP)
                    phk->iCurrentEvent++;

                if (phk->iCurrentEvent < phk->cEventMessages) {
                    *pEventMsg = phk->aEventCache[phk->iCurrentEvent];
                } else {

                    /*
                     * Free the cache set if it is still around
                     */
                    if (phk->aEventCache) {
                        UserFreePool(phk->aEventCache);
                        phk->aEventCache = NULL;
                    }
                    phk->cEventMessages = 0;
                    phk->iCurrentEvent = 0;

                    goto MakeClientJournalPlaybackCall;
                }

                /*
                 * Return the time and zero the batched time so if we sleep
                 * this time we won't sleep again next time
                 */
                nRet = pEventMsg->time;
                if (nRet)
                    phk->aEventCache[phk->iCurrentEvent].time = 0;
            } else if (nCode == HC_SKIP) {
                phk->iCurrentEvent++;
                nRet = 0;
            }

        } else {
#endif // HOOKBATCH
            /*
             * In order to avoid a client/server transition for HC_SKIP we
             * piggy-back it on top of the next journal playback event and
             * send it from there.
             */
// MakeClientJournalPlaybackCall:
            nRet = fnHkOPTINLPEVENTMSG(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                    (WPARAM)PtoHq(phk), (LPEVENTMSG)lParam, (ULONG_PTR)pfnHookProc,
                    ppfnClient->pfnDispatchHook);
#ifdef HOOKBATCH
        }

        /*
         * Determine if we received a cached set of events if so then store
         * them away off of the hook.
         * paramL will be the number of events.
         * paramH will be the array of events.
         */
        if ((nCode == HC_GETNEXT) && (((LPEVENTMSG)lParam)->message == 0x12341234)) {
            NTSTATUS Status;
            LPEVENTMSG pEventMsg = (LPEVENTMSG)lParam;

            /*
             * We should not be getting another cached set if we aren't
             * done with the first set
             */
            UserAssert((phk->cEventMessages == 0) ||
                    (phk->cEventMessages >= phk->iCurrentEvent));
            UserAssert((pEventMsg->paramL < 500) && (pEventMsg->paramL > 1));

            /*
             * Free the last cache set if it is still around
             */
            if (phk->aEventCache) {
                UserFreePool(phk->aEventCache);
                phk->aEventCache = NULL;
            }

            if (phk->aEventCache = LocalAlloc(LPTR,
                    pEventMsg->paramL*sizeof(EVENTMSG))) {
                PETHREAD Thread = PsGetCurrentThread();

                Status = ZwReadVirtualMemory(Thread->Process->ProcessHandle,
                        (PVOID)pEventMsg->paramH, phk->aEventCache,
                        pEventMsg->paramL*sizeof(EVENTMSG), NULL);

                if (NT_SUCCESS(Status)) {
                    phk->cEventMessages = pEventMsg->paramL;
                    phk->iCurrentEvent = 0;

                    /*
                     * Fill in the real EventMsg for this message
                     */
                    *pEventMsg = phk->aEventCache[0];
                    phk->aEventCache[0].time = 0;
                }

            } else {
                phk->cEventMessages = 0;
                phk->iCurrentEvent = 0;
            }
        }
#endif // HOOKBATCH

        phk->flags &= ~HF_NEEDHC_SKIP;
        break;

    case WH_JOURNALRECORD:

        nRet = fnHkOPTINLPEVENTMSG(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, (LPEVENTMSG)lParam, (ULONG_PTR)pfnHookProc,
                ppfnClient->pfnDispatchHook);
        break;

    case WH_DEBUG:
        /*
         * This takes an lpDebugHookStruct.
         */
        nRet = fnHkINLPDEBUGHOOKSTRUCT(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, (LPDEBUGHOOKINFO)lParam, (ULONG_PTR)pfnHookProc,
                ppfnClient->pfnDispatchHook);
        break;

    case WH_KEYBOARD_LL:
        /*
         * This takes an lpKbdHookStruct.
         */
        nRet = fnHkINLPKBDLLHOOKSTRUCT(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, (LPKBDLLHOOKSTRUCT)lParam,
                (ULONG_PTR)pfnHookProc, ppfnClient->pfnDispatchHook);
        break;

    case WH_MOUSE_LL:
        /*
         * This takes an lpMsllHookStruct.
         */
        nRet = fnHkINLPMSLLHOOKSTRUCT(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, (LPMSLLHOOKSTRUCT)lParam,
                (ULONG_PTR)pfnHookProc, ppfnClient->pfnDispatchHook);
        break;

    case WH_MOUSE:
        /*
         * This takes an lpMouseHookStructEx.
         */
MouseHook:
        nRet = fnHkINLPMOUSEHOOKSTRUCTEX(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, (LPMOUSEHOOKSTRUCTEX)lParam,
                (ULONG_PTR)pfnHookProc, ppfnClient->pfnDispatchHook, &phk->flags);
        break;

#ifdef REDIRECTION
    case WH_HITTEST:
        /*
         * This takes an lpHTHookStruct.
         */
        nRet = fnHkINLPHTHOOKSTRUCT(MAKELONG((UINT)nCode, (UINT)phk->iHook),
                wParam, (LPHTHOOKSTRUCT)lParam,
                (ULONG_PTR)pfnHookProc, ppfnClient->pfnDispatchHook);
        break;
#endif // REDIRECTION

    }

#ifdef LATER    // per 246329
    if (fLockForeground) {
        ThreadUnlockSFWLockCount(&tlSFWLock);
    }
#endif

    return nRet;
}

/***************************************************************************\
* fnHkINLPCWPEXSTRUCT
*
* This gets thunked through the message thunks, so it has the format
* of a c/s message thunk call.
*
* 05-09-91 ScottLu      Created.
\***************************************************************************/

LRESULT fnHkINLPCWPEXSTRUCT(
    PWND pwnd,
    UINT message,
    WPARAM wParam,
    LPARAM lParam,
    ULONG_PTR xParam)
{
    CWPSTRUCTEX cwp;
    PCLIENTINFO pci = GetClientInfo();
    BOOL        bInterThread;

    UNREFERENCED_PARAMETER(xParam);

    cwp.hwnd = HW(pwnd);
    cwp.message = message;
    cwp.wParam = wParam;
    cwp.lParam = lParam;
    cwp.psmsSender = NULL;
    try {
        bInterThread = (pci->CI_flags & CI_INTERTHREAD_HOOK) != 0;
    } except (W32ExceptionHandler(FALSE, RIP_WARNING)) {
        return 0;
    }

    return xxxCallNextHookEx(HC_ACTION, bInterThread, (LPARAM)&cwp);
}

LRESULT fnHkINLPCWPRETEXSTRUCT(
    PWND pwnd,
    UINT message,
    WPARAM wParam,
    LPARAM lParam,
    ULONG_PTR xParam)
{
    CWPRETSTRUCTEX cwp;
    PCLIENTINFO pci = GetClientInfo();
    BOOL        bInterThread;

    UNREFERENCED_PARAMETER(xParam);

    cwp.hwnd = HW(pwnd);
    cwp.message = message;
    cwp.wParam = wParam;
    cwp.lParam = lParam;
    cwp.psmsSender = NULL;
    try {
        cwp.lResult = pci->dwHookData;
        bInterThread = (pci->CI_flags & CI_INTERTHREAD_HOOK) != 0;
    } except (W32ExceptionHandler(FALSE, RIP_WARNING)) {
        return 0;
    }
    
    return xxxCallNextHookEx(HC_ACTION, bInterThread, (LPARAM)&cwp);
}