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gh-112278: add a new event to simulate COM init timeout in _wmi module #112878

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Merged
merged 1 commit into from
Dec 8, 2023
Merged

gh-112278: add a new event to simulate COM init timeout in _wmi module #112878

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46 changes: 34 additions & 12 deletions PC/_wmimodule.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -44,6 +44,7 @@ struct _query_data {
LPCWSTR query;
HANDLE writePipe;
HANDLE readPipe;
HANDLE initEvent;
HANDLE connectEvent;
};

Expand Down Expand Up @@ -81,13 +82,16 @@ _query_thread(LPVOID param)
IID_IWbemLocator, (LPVOID *)&locator
);
}
if (SUCCEEDED(hr) && !SetEvent(data->initEvent)) {
hr = HRESULT_FROM_WIN32(GetLastError());
}
if (SUCCEEDED(hr)) {
hr = locator->ConnectServer(
bstr_t(L"ROOT\\CIMV2"),
NULL, NULL, 0, NULL, 0, 0, &services
);
}
if (!SetEvent(data->connectEvent)) {
if (SUCCEEDED(hr) && !SetEvent(data->connectEvent)) {
hr = HRESULT_FROM_WIN32(GetLastError());
}
if (SUCCEEDED(hr)) {
Expand Down Expand Up @@ -193,6 +197,24 @@ _query_thread(LPVOID param)
}


static DWORD
wait_event(HANDLE event, DWORD timeout)
{
DWORD err = 0;
switch (WaitForSingleObject(event, timeout)) {
case WAIT_OBJECT_0:
break;
case WAIT_TIMEOUT:
err = WAIT_TIMEOUT;
break;
default:
err = GetLastError();
break;
}
return err;
}


/*[clinic input]
_wmi.exec_query

Expand Down Expand Up @@ -235,8 +257,11 @@ _wmi_exec_query_impl(PyObject *module, PyObject *query)

Py_BEGIN_ALLOW_THREADS

data.initEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
data.connectEvent = CreateEvent(NULL, TRUE, FALSE, NULL);
if (!data.connectEvent || !CreatePipe(&data.readPipe, &data.writePipe, NULL, 0)) {
if (!data.initEvent || !data.connectEvent ||
!CreatePipe(&data.readPipe, &data.writePipe, NULL, 0))
{
err = GetLastError();
} else {
hThread = CreateThread(NULL, 0, _query_thread, (LPVOID*)&data, 0, NULL);
Expand All @@ -251,16 +276,12 @@ _wmi_exec_query_impl(PyObject *module, PyObject *query)
// gh-112278: If current user doesn't have permission to query the WMI, the
// function IWbemLocator::ConnectServer will hang for 5 seconds, and there
// is no way to specify the timeout. So we use an Event object to simulate
// a timeout.
switch (WaitForSingleObject(data.connectEvent, 100)) {
case WAIT_OBJECT_0:
break;
case WAIT_TIMEOUT:
err = WAIT_TIMEOUT;
break;
default:
err = GetLastError();
break;
// a timeout. The initEvent will be set after COM initialization, it will
// take a longer time when first initialized. The connectEvent will be set
// after connected to WMI.
err = wait_event(data.initEvent, 1000);
if (!err) {
err = wait_event(data.connectEvent, 100);
}

while (!err) {
Expand Down Expand Up @@ -306,6 +327,7 @@ _wmi_exec_query_impl(PyObject *module, PyObject *query)
}

CloseHandle(hThread);
CloseHandle(data.initEvent);
CloseHandle(data.connectEvent);
hThread = NULL;

Expand Down