Re: [ECOS] Re: Network TCP Handler: stale socket disposal

[John Mills <johnmills at speakeasy dot net>]

All -

First, please excuse my attaching a patch here, but I would like to 
respond once (or a few times &8-) in case it's helpful.

Second, my reply to Mr. Singh failed posting because it originated from a 
reader that can't enforce text-only formatting. Sorry.

Third, I post this patch for test and discussion purposes. It seems to 
help in our limited case, but comes with no guarantee. I would appreciate 
hearing others' experience.

Thanks for your patience.

 - John Mills

On Tue, 25 Sep 2007, Alok Singh wrote:

> John,
 
> Please post it in whatever form you deem as appropriate.? Let us know
> when you will be able to post it.
 
> BTW, I'm seeing a similar issue in my application.? Sockets are
> exhausted, and web is not accessible.? Ping is going through. I've kept
> Max. number of sockets as 32 while configuring ecos. The strange thing
> is that the issue comes after a long period of inactivity, i.e., no web
> activity. ??
 
> Your patch will be useful.
 
> Regards,
> Alok ?

> ________________________________________
> From: John Mills [mailto:JMills@airdefense.net] 
> Sent: Tuesday, September 25, 2007 6:56 PM
> To: Alok Singh
> Cc: ecos-discuss@ecos.sourceware.org
> Subject: RE: [ECOS] Re: Network TCP Handler: stale socket disposal
 
> All -
 
> I don't believe my patch was ever accepted. The eCos sources carry a
> cautionary note that such a 'hung' socket may have been placed on the
> net stack 'accept' queue, and may be in the process of acceptance by a
> user thread which could then block.
 
> I checked Linux and FreeBSD man pages on this. In Linux the blocked task
> would receive the next such incoming client and be unblocked. This is
> perfect for my application. Neither OpenBSD nor FreeBSD man pages
> address the issue specifically.
 
> I didn't try to replicate the race condition myself.
 
> eCos now uses an older version of the BSD stack, and updating it looks
> significant - well over a month's work, maybe 3 or 4 based on the time
> the original author reported for his port.
 
> The patch solved a show-stopping problem with our application and seems
> to cause no problems, so we're using it. Two other users tried the
> approach and wrote me off-list: in one case it resolved a problem, in
> the other it made no difference (either way, as far as I know). I can
> share the patch on a "no warranty" basis, but would prefer to post it
> appropriately rather than circulating it randomly.
 
> ?- John Mills

Attachment: uipc_socket_c.pat
Description: Patch discards stale sockets

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