On 08.12.2013 19:32, Jeff Trawick wrote: > On Sun, Dec 8, 2013 at 8:56 AM, Jeff Trawick <traw...@gmail.com > <mailto:traw...@gmail.com>> wrote: > > On Tue, Nov 26, 2013 at 4:01 PM, Rainer Jung > <rainer.j...@kippdata.de <mailto:rainer.j...@kippdata.de>> wrote: > > On 26.11.2013 15:58, olli hauer wrote: > > On 2013-11-25 23:25, Jeff Trawick wrote: > > >> See if this brings any happiness: > >> > >> Index: network_io/unix/sockets.c > >> > =================================================================== > >> --- network_io/unix/sockets.c (revision 1545394) > >> +++ network_io/unix/sockets.c (working copy) > >> @@ -273,7 +273,7 @@ > >> #endif /* TCP_NODELAY_INHERITED */ > >> #if APR_O_NONBLOCK_INHERITED > >> if (apr_is_option_set(sock, APR_SO_NONBLOCK) == 1) { > >> - apr_set_option(*new, APR_SO_NONBLOCK, 1); > >> + /* apr_set_option(*new, APR_SO_NONBLOCK, 1); */ > >> } > >> #endif /* APR_O_NONBLOCK_INHERITED */ > > > > > > I can confirm after removing the line in apr-1.5.0 apache24 no > longer hangs. > > (tested with apache-2.4.6 / 2.4.7) > > > > I seen now why this is triggered by comparing apr.h after > `./configure', > > > >> grep APR_O_NONBLOCK_INHERITED work/apr-1.4.8/include/apr.h > > ./work/apr-1.4.8/include/apr.h:#define APR_O_NONBLOCK_INHERITED 0 > > > >> grep APR_O_NONBLOCK_INHERITED work/apr-1.5.0/include/apr.h > > work/apr-1.5.0/include/apr.h:#define APR_O_NONBLOCK_INHERITED 1 > > > > > >> There are some APR 1.5 autoconf changes to consider at > >> > > http://svn.apache.org/viewvc/apr/apr/branches/1.5.x/build/apr_network.m4?view=log > > > > OK, backing out the changes from r1502805 seems to do the > trick on 10b3 > > http://svn.apache.org/viewvc?view=revision&revision=1502805 > > > >> grep APR_O_NONBLOCK_INHERITED work/apr-1.5.0/include/apr.h > > work/apr-1.5.0/include/apr.h:#define APR_O_NONBLOCK_INHERITED 0 > > But acking out that change simply breaks the configure test on any > platform, because the resulting detection program no longer > compiles. > > So the real culprit, is that the detection isn't doing the right > thing. > > The test was changed before the compilation fix in the following > revision: > > > http://svn.apache.org/viewvc/apr/apr/branches/1.5.x/build/apr_network.m4?r1=887002&r2=1449569&pathrev=1502805&diff_format=h > > That was due to the fact that I saw the test providing unreliable > results on a busy machine. > > So the question to me is: is the O_NONBLOCK setting inherited from a > listening socket on FreeBSD 10 - that's what the test tries to > detect - > and how can we fix this feature test? > > > O_NONBLOCK is inherited from either an IPv6 listener or IPv4 > listener in the obvious case on FreeBSD (9 and 10 tested), where > "obvious" = V6ONLY in default setting (clearly ON), IPv6 client > socket used to connect to IPv6 server socket, IPv4 client socket > used to connect to IPv4 server socket. If I set V6ONLY to OFF, I > still see O_NONBLOCK inherited. > > This is with a pure sockets program, ruling out APR. > > > > Or: is the test correct, but it previously failed for systems, > where the > Apache or APR code does not do the right thing if the test would > have > succeeded. > > > I guess something about the real world scenario in httpd > (combination of other settings on the socket or presence of another > listener on the port or something else unexpected) is breaking this. > But I suppose there is other code that could be broken and needs to > be tested for completeness, such as failing to set non-blocking in > the listener but managing to set the flag in the APR socket. > > > I forgot that FreeBSD is a real OS (has source code for kernel installed) :) > > To make a long story short, FreeBSD 10 introduces accept4(). APR uses > accept4() where it can find it. accept4() on Linux and FreeBSD 10 both > have a SOCK_NONBLOCK flag, but on FreeBSD 10 the SOCK_NONBLOCK is the > sole determiner of whether or not the connected socket is non-blocking. > > (Recall that my binaries built on FreeBSD 9 worked fine.) > > So APR's use of accept4() was broken w.r.t. inherited non-blocking on > FreeBSD 10 but for a while we still worked because the configure-time > check didn't work right with clang (the normal compiler on FreeBSD 10). > > Once the clang issue was resolved, we hit the bad use of > accept4()-on-FreeBSD 10. > > I guess when calling accept4() and SOCK_NONBLOCK is defined we need to > set the SOCK_NONBLOCK flag if the listen socket is non-blocking, and not > worry about the more detailed semantics of accept4(). > > (untested as of yet, though I'm sure that will change in the next couple > of days) > > --/-- > > This is separate from the httpd issue -- fixing the FreeBSD version > check for --{enable|disable}-v6mapped, for which there is a patch > earlier in this thread.
... and the prize for the problem analysis of the week goes to Jeff! Regards, Rainer
