accept_filter, accf_http, setsockopt and the EINVAL error

[Sverre Froyen <sverre%viewmark.com@localhost>]

Hi,

I've been tracking down the cause of the

[warn] (22)Invalid argument: Failed to enable the 'httpready' Accept Filter

when pkgsrc/www/apache22 starts up.  It looks like apache does two identical 
calls on each socket when adding the "httpready" filters.  The first one 
succeeds, the second one fails with an EINVAL error.  This brings up two 
issues (ignoring the question of apache's behavior):

(1) It seems to me that adding the "httpready" filter a second time is not 
really an error and I'm wondering if setsockopt could be modified to silently 
ignore the second attempt.

(2) I'm unable to find a documented cause for the EINVAL.  Neither the 
setsockopt(2) nor the accf_http(9) mention this error.  Seems like at least 
set sockopt should mention it.

This is on amd64 current but I believe this applies to NetBSD 5 as well.

Regards,
Sverre