Bug fix for mod_fastcgi

[I posted this on 3/13, but nobody replied, and now I can't find it  
in the archives, so maybe the mailing list burped.  Here's trying  
again.]

I dug into the mod_fastcgi source, and believe I have found (and  
fixed) the problem with timeouts with certain-sized responses.   
Here's what's going on:

It can happen that we already have some data in the  
clientOutputBuffer before calling ap_select and fcgi_buf_socket_recv,  
to receive data into serverInputBuffer.  Then we call  
fcgi_protocol_dequeue, which will return after filling up  
clientOutputBuffer.  Then, if there is still more data to receive  
sitting on the socket itself, we're fine; ap_select will return  
happily on our next iteration and we finish processing the data.  But  
if not -- if we've emptied the socket into serverInputBuffer -- then  
ap_select times out, resulting in the "idle timeout" error.

So there are really two related problems here:

1. The socket_io method (which implements the main state machine)  
uses some heuristics to calculate how long it should wait before  
timing out.  This includes a check for pending data to be sent to the  
client (clientOutputBuffer) -- but does NOT include a check for data  
that's already been received from the socket and is waiting to be  
processed (serverInputBuffer).  I think in this case we want to just  
poll the sockets without waiting at all, so I added an additional  
block before the else clause:

		else if (BufferLength(fr->serverInputBuffer)) {
			/* data already in input buffer, so just poll sockets and continue */
			timeout.tv_sec = 0;
			timeout.tv_usec = 0;
		}

2. When we're in this situation, and ap_select returns 0 indicating  
that no knew data was found, we should not consider it an error as  
long as we still have pending data in serverInputBuffer.  So I  
changed the "if (select_status == 0)" line to

         if (select_status == 0 && !BufferLength(fr->serverInputBuffer))

With these changes, I'm now able to serve files of any size without  
hanging.

How and where do I go about submitting a patch to have this change  
reviewed and rolled into the standard distribution?

Thanks,
- Joe


--
Joe Strout
Inspiring Applications, Inc.
http://www.InspiringApps.com



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