[Dnsmasq-discuss] log_stderr + SIGPIPE

Simon Kelley simon at thekelleys.org.uk
Wed Sep 29 20:34:07 BST 2010

clemens fischer wrote:
> Simon Kelley wrote:
>> I'm pretty sure that writes will simply block if the reader at the
>> other end of the pipe is too slow. EPIPE occurs for the writer when
>> the reader actually closes the file descriptor.
> I see.
>> Of course if you were using a syslogd you could turn on asychronous
>> logging in dnsmasq and this problem would disappear....
> Good idea.  I usually use the per-process logger if I can help it,
> because then I don't get all sorts of daemon logs lumped together.
> There are other benefits as well.  OTOH, if it avoids that deadlock,
> I'll switch to using some syslog variant that has good filtering.

If you determine that the problem really is the daemon-manager blocking
stderr, it might be worth an experiment: at the moment logging to a file
(including stderr) automatically forces asynchronous logging to be
disabled. I don't see there's any reason to do that, so a simple change
could make --log-async valid with --log-facility=-



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