[Dovecot] lmtp panic in proxy lmtp director

[Timo Sirainen]

On Mon, 2011-12-05 at 15:26 +0100, Xavier Pons wrote:
> Hi, we are getting some  core dumps with signal 6 in ltmp on a dovecot 
> director proxy server,
> like this:
> 
> Dec  5 14:31:51 sproxy1 dovecot: lmtp(29999): Panic: file lmtp-proxy.c: 
> line 376 (lmtp_proxy_output_timeout): assertion failed: 
> (proxy->data_input->eof)

I think the way I originally planned LMTP proxying to work is simply too
complex to work reliably, perhaps even if the code was bug-free. So
instead of reading+writing DATA at the same time, this patch changes the
DATA to be first read into memory or temp file, and then from there read
and sent to the LMTP backends:

http://hg.dovecot.org/dovecot-2.1/raw-rev/51d87deb5c26

The patch applies on top of v2.0 also. I tested that it appears to work,
but more testing wouldn't hurt to make sure it won't corrupt large mails
when sending them to multiple backends (one mail with multiple RCPT TOs
sent to multiple different backends)..