Am 04.11.2011 10:46, schrieb Paolo Bonzini: > On 10/28/2011 02:17 PM, Paolo Bonzini wrote: >>> Yes, it would be better if we could have error output on stderr. Now, >>> "simple" errors such as a missing image file (or wrong path to the >>> image) are reported to syslog instead. It could be the source of some >>> headaches... >>> >>> Is there a way we could have the child send the error to the parent >>> over a pipe and have the parent print it on stderr? >> >> A way could be to change the fork() into a separate thread, so that you >> can daemonize as soon as you accept the socket rather than having to do >> it early. > > I tried implementing this, but in general daemonization (which forks and > leave only the children) breaks the threading. > > So we could either keep this series (which moves all errors to syslog, > but doesn't otherwise change behavior), or I can finish and post an > alternative series that removes all forking from qemu-nbd *but* changes > behavior in that "qemu-nbd -c" will not daemonize anymore. > > Since this is 1.0 after all, I'm slightly more inclined towards the latter. > > Opinions? Kevin, Anthony?
I'm surprised that -c is what causes trouble. As far as I understand, the code for implementing -c doesn't use the qemu block layer at all. So why can't we just change the code to fork before it initialises the block layer and opens the image file? Kevin
