From: Jeff Hostetler <git@jeffhostetler.com>
Date: Thu, 03 Mar 2022 16:16:01 GMT
Subject: Re: [PATCH 17/23] fsmonitor--daemon: stub in health thread
Message-ID: <5bb246d3-82d0-835a-cfc4-be2824479a82@jeffhostetler.com>
In-Reply-To: <4c784936-7b70-3910-6413-0438e86b23c4@github.com>



On 2/24/22 11:04 AM, Derrick Stolee wrote:
> On 2/15/2022 10:59 AM, Jeff Hostetler via GitGitGadget wrote:
>> From: Jeff Hostetler <jeffhost@microsoft.com>
>>
>> Create another thread to watch over the daemon process and
>> automatically shut it down if necessary.
>>
>> This commit creates the basic framework for a "health" thread
>> to monitor the daemon and/or the file system.  Later commits
>> will add platform-specific code to do the actual work.
> 
> ...
...
> 
>> diff --git a/compat/fsmonitor/fsm-health-win32.c b/compat/fsmonitor/fsm-health-win32.c
>> new file mode 100644
>> index 00000000000..94b1d020f25
>> --- /dev/null
>> +++ b/compat/fsmonitor/fsm-health-win32.c
>> @@ -0,0 +1,72 @@
>> +#include "cache.h"
>> +#include "config.h"
>> +#include "fsmonitor.h"
>> +#include "fsm-health.h"
>> +#include "fsmonitor--daemon.h"
>> +
>> +struct fsm_health_data
>> +{
>> +	HANDLE hEventShutdown;
>> +
>> +	HANDLE hHandles[1]; /* the array does not own these handles */
>> +#define HEALTH_SHUTDOWN 0
>> +	int nr_handles; /* number of active event handles */
>> +};
>> +
>> +int fsm_health__ctor(struct fsmonitor_daemon_state *state)
>> +{
>> +	struct fsm_health_data *data;
>> +
>> +	CALLOC_ARRAY(data, 1);
>> +
>> +	data->hEventShutdown = CreateEvent(NULL, TRUE, FALSE, NULL);
>> +
>> +	data->hHandles[HEALTH_SHUTDOWN] = data->hEventShutdown;
>> +	data->nr_handles++;
>> +
>> +	state->health_data = data;
>> +	return 0;
>> +}
>> +
>> +void fsm_health__dtor(struct fsmonitor_daemon_state *state)
>> +{
>> +	struct fsm_health_data *data;
>> +
>> +	if (!state || !state->health_data)
>> +		return;
>> +
>> +	data = state->health_data;
>> +
>> +	CloseHandle(data->hEventShutdown);
>> +
>> +	FREE_AND_NULL(state->health_data);
>> +}
>> +
>> +void fsm_health__loop(struct fsmonitor_daemon_state *state)
>> +{
>> +	struct fsm_health_data *data = state->health_data;
>> +
>> +	for (;;) {
>> +		DWORD dwWait = WaitForMultipleObjects(data->nr_handles,
>> +						      data->hHandles,
>> +						      FALSE, INFINITE);
>> +
>> +		if (dwWait == WAIT_OBJECT_0 + HEALTH_SHUTDOWN)
>> +			goto clean_shutdown;
>> +
>> +		error(_("health thread wait failed [GLE %ld]"),
>> +		      GetLastError());
>> +		goto force_error_stop;
>> +	}
>> +
>> +force_error_stop:
>> +	state->health_error_code = -1;
>> +	ipc_server_stop_async(state->ipc_server_data);
>> +clean_shutdown:
>> +	return;
>> +}
>> +
>> +void fsm_health__stop_async(struct fsmonitor_daemon_state *state)
>> +{
>> +	SetEvent(state->health_data->hHandles[HEALTH_SHUTDOWN]);
>> +}
> 
> But it apppears the Windows code is actually implemented. Did you
> mean to do that as separate step, or should the commit message
> mention that the Windows implementation is included?

The Windows version stubs in just enough of the thread-proc to keep
the health thread alive and waiting for a shutdown event.  It doesn'ta
actually have any health monitor in it yet.

I'll update the commit message to clarify.

Thanks
Jeff