[syslog-ng]PTR lookups; leak/crash fixes

[Scott McDermott]

Why does syslog-ng do a PTR lookup for EVERY message?

It uses them for $HOST stuff? But why not cache these and avoid the
lookup? At first I thought, the caching belongs in the libc, possibly in
nscd.  But despite nscd running (this is Linux with glibc-2.1),
gethostbyaddr() still does a full name server PTR lookup for every
single message.  I started running a slave name server on the localhost
just to avoid the bandwidth hit doing all these queries :) But now there
is a bunch of extra CPU usage (syslog-ng has accumulated 600 minutes of
CPU time after running for just one day; this is a 333Mhz machine and
there are only a couple dozen logging hosts, most of which comes relayed
through other syslog-ngs anyways).

If I were to set use_dns to `no' this would probably make the problem go
away.  Is there any reason not to do this? Would I then get IPs for
$HOST instead of names?

Incidentally, the assert fix definitely got rid of the crashing, and the
string free definitely fixed some memory leakage.  But I have only been
running it for one day and it's up to 6 meg VSZ so far (would have been
30 by now before the fix) ...hopefully this is just some data structures
which will plateau out once it's been running for some time (xinetd does
this in a big way ;)