LONG WINAPI DetourDetach()

in Detours/detours.cpp [2140:2277]

• 121 lines of code
• 14 McCabe index (conditional complexity)

LONG WINAPI DetourDetach(_Inout_ PVOID *ppPointer,
                         _In_ PVOID pDetour)
{
    LONG error = NO_ERROR;

    if (s_nPendingThreadId != (LONG)GetCurrentThreadId()) {
        return ERROR_INVALID_OPERATION;
    }

    // If any of the pending operations failed, then we don't need to do this.
    if (s_nPendingError != NO_ERROR) {
        return s_nPendingError;
    }

    if (pDetour == NULL) {
        return ERROR_INVALID_PARAMETER;
    }
    if (ppPointer == NULL) {
        return ERROR_INVALID_HANDLE;
    }
    if (*ppPointer == NULL) {
        error = ERROR_INVALID_HANDLE;
        s_nPendingError = error;
        s_ppPendingError = ppPointer;
        DETOUR_BREAK();
        return error;
    }

    DetourOperation *o = new NOTHROW DetourOperation;
    if (o == NULL) {
        error = ERROR_NOT_ENOUGH_MEMORY;
      fail:
        s_nPendingError = error;
        DETOUR_BREAK();
      stop:
        if (o != NULL) {
            delete o;
            o = NULL;
        }
        s_ppPendingError = ppPointer;
        return error;
    }


#ifdef DETOURS_IA64
    PPLABEL_DESCRIPTOR ppldTrampo = (PPLABEL_DESCRIPTOR)*ppPointer;
    PPLABEL_DESCRIPTOR ppldDetour = (PPLABEL_DESCRIPTOR)pDetour;
    PVOID pDetourGlobals = NULL;
    PVOID pTrampoGlobals = NULL;

    pDetour = (PBYTE)DetourCodeFromPointer(ppldDetour, &pDetourGlobals);
    PDETOUR_TRAMPOLINE pTrampoline = (PDETOUR_TRAMPOLINE)
        DetourCodeFromPointer(ppldTrampo, &pTrampoGlobals);
    DETOUR_TRACE(("  ppldDetour=%p, code=%p [gp=%p]\n",
                  ppldDetour, pDetour, pDetourGlobals));
    DETOUR_TRACE(("  ppldTrampo=%p, code=%p [gp=%p]\n",
                  ppldTrampo, pTrampoline, pTrampoGlobals));


    DETOUR_TRACE(("\n"));
    DETOUR_TRACE(("detours:  &pldTrampoline  =%p\n",
                  &pTrampoline->pldTrampoline));
    DETOUR_TRACE(("detours:  &bMovlTargetGp  =%p [%p]\n",
                  &pTrampoline->bMovlTargetGp,
                  pTrampoline->bMovlTargetGp.GetMovlGp()));
    DETOUR_TRACE(("detours:  &rbCode         =%p [%p]\n",
                  &pTrampoline->rbCode,
                  ((DETOUR_IA64_BUNDLE&)pTrampoline->rbCode).GetBrlTarget()));
    DETOUR_TRACE(("detours:  &bBrlRemainEip  =%p [%p]\n",
                  &pTrampoline->bBrlRemainEip,
                  pTrampoline->bBrlRemainEip.GetBrlTarget()));
    DETOUR_TRACE(("detours:  &bMovlDetourGp  =%p [%p]\n",
                  &pTrampoline->bMovlDetourGp,
                  pTrampoline->bMovlDetourGp.GetMovlGp()));
    DETOUR_TRACE(("detours:  &bBrlDetourEip  =%p [%p]\n",
                  &pTrampoline->bCallDetour,
                  pTrampoline->bCallDetour.GetBrlTarget()));
    DETOUR_TRACE(("detours:  pldDetour       =%p [%p]\n",
                  pTrampoline->ppldDetour->EntryPoint,
                  pTrampoline->ppldDetour->GlobalPointer));
    DETOUR_TRACE(("detours:  pldTarget       =%p [%p]\n",
                  pTrampoline->ppldTarget->EntryPoint,
                  pTrampoline->ppldTarget->GlobalPointer));
    DETOUR_TRACE(("detours:  pbRemain        =%p\n",
                  pTrampoline->pbRemain));
    DETOUR_TRACE(("detours:  pbDetour        =%p\n",
                  pTrampoline->pbDetour));
    DETOUR_TRACE(("\n"));
#else // !DETOURS_IA64
    PDETOUR_TRAMPOLINE pTrampoline =
        (PDETOUR_TRAMPOLINE)DetourCodeFromPointer(*ppPointer, NULL);
    pDetour = DetourCodeFromPointer(pDetour, NULL);
#endif // !DETOURS_IA64

    ////////////////////////////////////// Verify that Trampoline is in place.
    //
    LONG cbTarget = pTrampoline->cbRestore;
    PBYTE pbTarget = pTrampoline->pbRemain - cbTarget;
    if (cbTarget == 0 || cbTarget > sizeof(pTrampoline->rbCode)) {
        error = ERROR_INVALID_BLOCK;
        if (s_fIgnoreTooSmall) {
            goto stop;
        }
        else {
            DETOUR_BREAK();
            goto fail;
        }
    }

    if (pTrampoline->pbDetour != pDetour) {
        error = ERROR_INVALID_BLOCK;
        if (s_fIgnoreTooSmall) {
            goto stop;
        }
        else {
            DETOUR_BREAK();
            goto fail;
        }
    }

    DWORD dwOld = 0;
    if (!VirtualProtect(pbTarget, cbTarget,
                        PAGE_EXECUTE_READWRITE, &dwOld)) {
        error = GetLastError();
        DETOUR_BREAK();
        goto fail;
    }

    o->fIsRemove = TRUE;
    o->ppbPointer = (PBYTE*)ppPointer;
    o->pTrampoline = pTrampoline;
    o->pbTarget = pbTarget;
    o->dwPerm = dwOld;
    o->pNext = s_pPendingOperations;
    s_pPendingOperations = o;

    return NO_ERROR;
}