Portable way for testing listening sockets

[Jean-Yves Migeon <jym%helkyn.org@localhost>]

Hi everyone,

I got a package (apache-solr) for which I need a portable, sh-posixish
way of testing for the presence of a listening socket. FreeBSD "fixed"
it by patching over lsof and use their sockstat(1) instead:

https://svnweb.freebsd.org/ports/head/textproc/apache-solr/files/patch-bin_solr?view=markup&pathrev=438757

I'd like to avoid this in the pkg. What would be the acceptable form for
this, considering that even sockstat(1) syntax can differ from one OS to
another?

Having lsof in DEPENDS just for this seems kind of overkill.

Thanks,

-- 
Jean-Yves Migeon