Hello!

On Wed, May 20, 2015 at 01:03:19PM -0400, donatasm wrote:

> I'm trying to build a simple timeout module using nginx timers. At the
> beginning of a request I'm firing up a timer and after time interval elapses
> I want to check if request has already completed, and if not, finalize it,
> for example it with NGX_HTTP_REQUEST_TIME_OUT. I have created a filter
> module. I'm creating a timer in filter headers:
>
> static ngx_int_t simple_timeout_filter_headers(ngx_http_request_t* request)
> {
> ngx_event_t* timeout_event;
>
> timeout_event = ngx_pcalloc(request->pool, sizeof(ngx_event_t));
> if (timeout_event == NULL)
> {
> return NGX_ERROR;
> }
>
> timeout_event->handler = simple_timeout_handler;
> timeout_event->data = request;
> timeout_event->log = request->connection->log;
>
> ngx_log_debug0(NGX_LOG_DEBUG_HTTP, request->connection->log, 0,
> "SIMPLE TIMEOUT TIMER START");
>
> ngx_add_timer(timeout_event, 3000); /* wait for 3 seconds */
>
> return next_header_filter(request);
> }
>
> Simple timeout handler looks like this:
>
> static void simple_timeout_handler(ngx_event_t* timeout_event)
> {
> ngx_log_debug0(NGX_LOG_DEBUG_HTTP, timeout_event->log, 0,
> "SIMPLE TIMEOUT TIMER END");
> }
>
> And it works if I issue a request, and wait for a timer to fire. If I issue
> several requests while the previous timer is already in progress, I get a
> SEGFAULT.

At least you don't remove the timer if the request completes
before the timer is triggered. This is enough to trigger a
segmentation fault.

--
Maxim Dounin
http://nginx.org/

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