1.7.1: Bind 9.6.0-P1 on Vista: could not listen on UDP socket: not enough free resources (patch attached)

mki-cygwin@mozone.net mki-cygwin@mozone.net
Sun May 23 13:51:00 GMT 2010


On Sat, May 22, 2010 at 11:48:09AM -0400, Christopher Faylor wrote:
> On Sat, May 22, 2010 at 05:01:11AM -0700, mki-cygwin@mozone.net wrote:
> >The workaround I found was to recompile the sources, but making sure
> >that -DFD_SETSIZE=16384 is defined during the configure stage.  Patch
> >attached below.
> >
> >Can someone please update the port with this bumped up FD_SETSIZE patch?
> 
> If FD_SETSIZE is used to control what goes into one of the fd_set arguments
> to select() this won't work too well.
> 
> fd's are allocated monotonically starting with 0 so if accept() is really 
> returning something greater than 63 someone should figure out why.

Actually digging into it, named requires at least a minimum of 128.  It 
then, as a result, issues fcntl(fd, FD_DUPFD, reserved), where reserved is
the minimum value of 128 if the socket is determined to be a udp one.
If fd's greater than 64 were truely invalid then duping the fd with the
reserved range greater than 64 should have resulted in -1 with errno of 
EBADF just like select did.

Besides, I believe the only deficiency here is that bind's configure
isn't smart enough to auto correct the FD_SETSIZE when it detects it's
under cygwin.  Other utilities more than likely already do this part 
automatically for you during the configure stage...

Anyhow, I did a private build using cygport and the patch attached in my
previous response, and the resulting named (and utilities/libraries) are
working quite well.

Mohan

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